American Geographical SocietyTransport Expansion in Underdeveloped Countries: A Comparative AnalysisAuthor(s): Edward J. Taaffe, Richard L. Morrill and Peter R. GouldSource: Geographical Review, Vol. 53, No. 4 (Oct., 1963), pp. 503-529Published by: American Geographical SocietyStable URL: http://www.jstor.org/stable/212383 .Accessed: 17/02/2014 03:51Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp .JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org. .American Geographical Society is collaborating with JSTOR to digitize, preserve and extend access toGeographical Review.http://www.jstor.org This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORTEXPANSIONINUNDERDEVELOPED COUNTRIES:ACOMPARATIVEANALYSIS* EDWARD J.TAAFFE, RICHARDL. MORRILL, ANDPETERR.GOULD IN THEeconomic growth of underdeveloped countriesa criticalfactorhas beenthe improvement of internal accessibilitythrough the expansion of a transportation network.This expansion is from its beginning at once a continuous process of spatial diffusionandan irregular or sporadicprocess in- fluenced by manyspecific economic,social, or political forces.In the present paper both processes areexaminedas they havebeenevidentin the growth of modern transportation facilitiesinseveral underdeveloped areas.Certain broad regularitiesunderlying the spatial diffusion process are brought to light, which permit a descriptivegeneralization ofan ideal-typicalsequence of transportationdevelopment. The relationship between transportation and population isdiscussedand is used as the basisfor examinationofsuch additionalfactorsasthe physical environment, rail competition, intermediate location, andcommercialization. Throughout the study, Ghanaand Nigeria areusedas examples.' SEQUENCE OFTRANSPORTATIONDEVELOPMENT Figure 1 presents the authors' interpretation of an ideal-typicalsequence of transportdevelopment. The first phase(A) consistsof a scattering of small ports and tradingpostsalong the seacoast.Thereis littlelateralinterconnec- tion except for small indigenousfishing craft and irregularly scheduled trading vessels, and each port has an extremely limited hinterland.With the emergence of major lines of penetration(B), hinterland transportation costsare reducedfor certain ports. Markets expand both at the port and at the interiorcenter.Port concentrationthen begins, as illustrated by the * This study is based on a combination of the findings in Edward J. Taaffe and Richard L. Morrill: TransportationGeography Research: Part 2, Investigation of the Internal Spatial Distribution of Trans- portation Facilities (unpublishedreport tothe U.S. ArmyTransportation Research Command under the auspices of the Transportation Center at Northwestern University,July 1, 1960); and Peter R.Gould: The Development of the Transportation Pattern in Ghana, NorthwesternUniv. Studiesin Geogr. No. 5, Evanston, Ill.,1960. Other areasexamined in some detail, though from secondarysources, are Brazil, Kenya, Tangan- yika, and Malaya. >DR.TAAFFEis professor of geography atTheOhioState University, Columbus. DR.MORRILLisassistant professor of geography atthe University of Washington, Seattle. DR.GOULDisassistant professor of geography atThe Pennsylvania State University, Uni- versity Park. This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW IDEAL-TYPICAL SEQUENCE OF TRANSPORTDEVELOPMENT A ScatteredPorts pi CC '?f PenetrationLinesand Port Concentration D Beginnings ofInterconnection C E Complete Interconnection Development ofFeeders- GEOGR.REVV nOCT. 1q96 Emergence of High-Priority- "MainStreets" FIG.1 A B C .4 504 A I1 ? This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES circles P1 and P2. Feeder routes begin tofocus onthe major ports and in- terior centers (C). These feeder routes give rise to a sort of hinterland piracy that permits the major port to enlarge its hinterlandat the expense ofad- jacent smaller ports. Small nodes begin to develop along the main lines of penetration, and as feeder development continues (D), certain of the nodes, exemplifiedby N1 and N2, become focal points for feeder networks oftheir own.Interior concentrationthen begins, and N1 and N2 pirate the hinter- lands ofthe smaller nodes oneach side. Asthe feeder networks continue to develop aroundthe ports, interior centers, and main on-line nodes, certain ofthe larger feeders begin tolink up(E). Lateral interconnection should theoretically continue until all the ports, interior centers, and main nodes are linked. It is postulated that once this level is reached, oreven before, the next phase consists ofthe development of national trunk-line routes or "main streets" (F). In a sense, this is the process ofconcentration repeated, but at a higher level.Since certain centers will grow at the expense ofthe others, the result willbe a set of high-priority linkages among the largest. For example, in the diagram the best rail schedules, the widest paved roads, and the densestair trafficwould be over the P1-I2 and P1-P2 routes. It is probably most realistictothink ofthe entire sequence as a process ratherthan as a series of discretehistorical stages.2 Thus at a given point in time a country's total transportpatternmay show evidence of all the phases. Lateralinterconnection may be going oninone region at thesame time that new penetration lines are developing in another. THEFIRST PHASE:SCATTERED PORTS In bothGhana and Nigeria3 an early period ofnumerous small, scattered ports and coastal settlementswith trading functions may be easily identified (Figs. 3 and 4). These settlements, most of which existed or came into being 2 It is interesting to note a few analogies to some of W.W.Rostow's stages of economic develop- ment. The scattered,weakly connected ports might be consideredevidences of the isolation of Rostow's traditional society; the development of a penetration line might be viewed as a sort of spatial "takeoff"; the lateral-interconnection phase might bea spatial symptom ofthe internal diffusion of technology; and the impact of the auto on the latter phases of the sequencemight be an expression of the emergence ofcertain aspects ofan era of higher mass consumption in underdeveloped countries. 3 For Ghana, the examples arebasedon the field dataand primary statisticalsourcematerial gathered by Peter R.Gould. For Nigeria, primary statisticalsources are indicated where necessary. Secondary sourcesinclude Kenneth O. Dike: Trade and Politics in the Niger Delta, 1830-1885 (Oxford Studiesin African Affairs;London, 1956); Gilbert Walker: Trafficand Transport in Nigeria: The Example of an Underdeveloped Tropical Territory, ColonialResearchStudiesNo. 27, Colonial Office, London, 1959; "The Economic Development of Nigeria" (International Bank for Reconstruction and Development, Baltimore, 1955). The authorsare also indebted to Dr. Akin Mabogunje, of University College, Ibadan, for his comments. 505 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW between the end of the fifteenth century and the end of the nineteenth, were populated by the indigenous people around a European trading station or fort. Many of the people engaged in trade with the Europeans and served as middlemenfor tradewith the interior, a function jealously guarded for cen- turies againstEuropean encroachment.Penetrationlines to the interior were weakly developed, but networks of circuitousbush trailsconnectedthe small centers totheir restrictedhinterlands.Rivermouths were important, par- ticularly inthe Niger delta, butwithafew exceptions during the early periods of European encroachmentthe rivers did not develop as the main lines ofthrust when penetrationbegan. Most ofthese early trading centers have long since disappeared, destroyedby the growth of the main ports, or else they linger on as relict ports, with visits of occasional tramp steamersto remind them of their former tradingheyday. THESECONDPHASE:PENETRATION LINESANDPORTCONCENTRATION Perhaps themost important single phase inthe transportationhistory of an underdevelopedcountry is the emergence of the first majorpenetration line from the seacoasttothe interior. Later phases typically evolve around the penetration lines, and ultimately there is a strong tendency for them to serve as the trunk-lineroutes for more highly developed transportation net- works. Three principal motives for building lines of penetration have been active inthe past: (1) thedesire toconnect anadministrativecenter on theseacoast withaninterior area for political and military control; (2) thedesire toreach areas ofmineral exploitation; (3) thedesire toreach areasof potential agriculturalexport production. In the cases examined, the political motive has been the strongest. Political and military control dom- inated official thinking of the day in Africa, often as a direct result of extra- Africanrivalries.The second motive, mineral exploitation, is typically asso- ciated with rail penetration. It is today probably the principal motive for the building of railways in Africa, andthen only after careful surveys and international agreements have virtually guaranteed the steady haul of a bulk commodity to amortizethe loans required for construction.4 The development ofa penetration line sets in motion a series of spatial processes and readjustments as the comparative locational advantages ofall centers shift. Concentrationof port activity is particularlyimportant, and 4 For example, the extension of the Uganda railway to Kaseseto haul copper ore; the long north- ward extension ofthe Cameroon railway from Yaounde toGaroua tohaul manganese; and the new railway from Port-Etienneto Fort Gouraudin Mauritaniato haul iron ore. 506 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES Oda ?e Coast /~Kekonal GHANA CHANGESINPORTCONCENTRATION CIRCLES PROPORTIONAL TO TOTAL VALUE OF GOODSHANDLED IN THOUSANDSOF POUNDSSTERLING '":!"'" 320-1000 1000-4000 Over 40002040.60 Miles FIG. 2-Changes in port concentration, Ghana, 1900-1925. Redrawnfrom map in Gould, The Development ofthe Transportation Pattern inGhana (see starred footnotein text), p. 45. 1-80 80-160 1 160-320 507 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsFIG. 3-Majortransport facilities, Ghana. Generalizedfrom several maps in Gould, The Development ofthe Transportation Pattern inGhana (see starredfootnote in text). FIG. 4-Majortransport facilities, Nigeria. Adapted from Map 1 in "The Economic Development of Nigeria" (see text footnote 3 above). MAJORTRANSPORT FACILITIES : ::-:+ i -+Railroads ------Mainroads * Former trading posts This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES the ports at the terminiof the earliest penetration linesare usually the ones that thrive at the expense of their neighbors (Fig. 2).Typically, one or two ports ina country dominate both import and export traffic, and often the smaller ports have lost their functions in externalcommerce. In Ghana several interesting variationsonthe penetration theme appear (Fig. 3). Thedesire toreach Kumasi, capital ofa then aggressive Ashanti, formedthe essentially military-political motiveforthefirst penetration road, which followed an old bush track, sporadically cleared whenever the local people were goaded into activity. The road was built from Cape Coast, and although it is still important as one of Ghana'smain north-south links, the port function of Cape Coast declined as Sekondi increasedin importance. Sekondi's great impetus came with the building of the rail penetration line to Kumasiat the turn of the century, afterwhich adjacentports such as Axim, Dixcove, Adjua, Shama, Komena, and Elmina suffereda rapid decline in traffic.The Pra and Ankobra Rivers, east and west of Sekondi, which were formerly ofsome significance as avenues of penetration, also experienced marked traffic decreases.Theinitial motiveforthewestern railroad was primarily mineral production (the goldfield at Tarkwa), and secondarily provision of a rapid connection for administrationbetween the seacoastand a troublesomeinternalcenter of population. Theeasternrailroad penetration line was slower in developing, partly as a result of the interruption of the FirstWorld War and of smallpox out- breaksin the railroad camps. The link between Kumasi and Accra was not completed until 1923, twenty years after the Sekondi-Kumasilink. Connec- tionwiththe rapidly expanding cocoa areas north ofAccra was the im- mediate reasonfor this line, underlain by the political desire to connect the leading city, Accra, with Kumasi, the main population and distributioncen- ter in the interior.As in the case of Sekondi-Takoradi, Accra's importance in- creased steadily at the expense of adjacentports as the railroad penetrated inland. Thetwo penetration lines forming thesides oftherail triangle were now complete, and a considerableamount of subsequenttransportation de- velopment ofthe country was based onthese twotrunk lines. Penetration north of Kumasi was entirely by road, despite grand railroad plans at one time.There were nominerals to provide an economic incentive forrail- roads, and the barrenmiddle zone, which separated the rail-triangle areafrom the densely settled north, acted as a deterrentto the continuationof the rail- road in short stages. The Great North Road is the chief line of penetration north of Kumasi, 509 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW built witha strong political-administrative motive to Tamale, atown deliberately laid out as the capital of the NorthernTerritoriesin the early years of this century.Early feeder developmentfocusing on Tamale helped to fix the position of thistrunkline andits extensionto thenorthernmarkets of Bolgatanga,Navrongo, andBawku.The WesternTrunkRoad was built with similarmotivesand grew out of theextensiveKumasifeedernetworkto link that city with a moderatelypopulated areanorthof the barrenmiddle zone. In the building of the EasternTrunkRoad political and economic motives were mixed. This road through former British Togoland was originally extendedfrom the Hohoe cocoa areato Yendi for transport of yams to the rapidlygrowing urbancentersof the south, but its extensionto the northernborder hinged in largepart on political motivesthatwere very strongimmediately beforethe UnitedNations plebiscite and Togo's resultant political affiliationwith Ghana.The original roadlinksfrom the rail triangle and Accrato the Hohoe cocoa areawere associatedwith a political desire to forge a linkwithBritish Togoland, andwith aneconomicdesireto prevent the diversionof thisarea'scocoatrafficto the port of Lomein then-French Togoland. The process of penetration and port concentrationin Nigeria(Fig.4) was markedly similarto that in Ghana; the main difference lay in the greater emphasis on long-haul rail development and the subsequenthigher level of economic development in the north. Again the initialmotiveswere some- what more political than economic; for even the earlypenetration to the northvia the Niger River by the Royal Niger Company had imperialistic as well as economicmotives.In a sense, Kano might be regarded as analogous to Kumasi.Both are important interiorcenterswhich predateEuropean set- tlementandwhichwerelaterconnectedto the main portsby rail penetration lines.The chief differences, of course, arethe vastlygreater distancebetween Kano and the coast and the greater width of Nigeria'srelatively barren middlezone.Mineral exploitation wasalsoa major motivefor the building of rail penetration lines in Nigeria,particularly the easternrailroad.The line fromPortHarcourtwasstartedin 1913 andwas connectedwith the impor- tant Enugu coalfieldsthree years later.This port servesalsoas the principal outletfor the tin output of the Jos Plateau.The connecting of agricultural regions to the coast, though not a strong initial penetration motive, was ap- parently associatedwith the actual linking of thenorthernandsouthernlines. As in Ghana, the rail penetration lines form the basisfor the entire transportation network.The only areaof extensiveroad penetration is in the northeast, from the railroadat Jos and Nguru to Maiduguri. The main 510 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES motivefor establishing tarredroadsand large-scaletrucking serviceswas the attractionof theLakeChad region to thenortheast. However, the Maiduguri region is now being connected by railto the main network, despite the rec- ommendationof a missionof the InternationalBankfor Reconstructionand Development, whichfelt thatroadscouldmore efficiently accommodatethe expected increasein traffic.In the southeastthereis no effectiveroador rail penetration line. Portconcentrationhasbeenmarked.The declineof the delta portsbegan with the building of the rail penetration linefrom Lagos andwasaccentuated by the building of the easternline andthe concomitant growth of PortHar- court.In 1958 thesetwo majorports accountedfor morethan three-quarters of Nigeria'sexport and import trade. THETHIRDPHASE:FEEDERS ANDLATERAL INTERCONNECTIONS Penetrationis followed by lateralinterconnectionas feederlines begin to move out bothfromthe ports andfromthenodes along the penetration lines. The process of concentration among the nodesis analogous to the process of port concentration; it resultswhen the feedernetworksof certaincenters reachout and tap the hinterlandsoftheir neighbors. As feedernetworks become stronger at the interiorcentersandintermediatenodessomeof them link and thereby interconnectthe originalpenetration lines.5 Figures 5, 6, and 7 present a sequence of road development in Ghanafrom 1922 to 1958. The shading representsroad-mileagedensity as recordedin a seriesof grid cellsof 283 square miles superimposed on a highwaymap. In 1922 Ghanahad just enteredthe phase of lateral interconnection, with east- west linkages both in the south, along the coast, and among the centersof the north, andwith an extensivefeedernetwork steadilydrawing moreand more of the smaller population centersinto the orbitof Kumasi. Develop- ment in the southwestwas weak, owing to railroad competition and to a deliberate policy of maintaining an economicroad gap betweenSekondi- TakoradiandKumasi.This gap was finally filledin 1958, and only now is the southwest beginning to realizeits greatpotential in cocoa and timber. By 1937 lateralinterconnectionhadbecomemoremarked.The connectionseast andwest of Tamale provide a good example of linksbetweenintermediate nodes. The 1-20-mile shading, for example, nowreacheswest from the 5 The degree of interconnectednessof a transport network could be precisely evaluated by the use of such new measuresas those presented in William L. Garrison: Connectivity of the Interstate Highway System, Papers andProc. Regional Science Assn., Vol.6 (6th Annual Meeting), 1960 (Philadelphia,1961), pp. 121-137. 511 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsMILESPERGRID CELLOF 283 SQUAREMILES GHANA o20406080100120140 ROADDENSITY Railways _ More than 80 61 to 8041to 60 46 81 20 1 4 ROAD DENSITYJrMileM :::ROAD DENSIY 21 to40 '- 1 to 20 M 0 GEOGR.REV,,OCT., 1963 FIG. 5-7-Roaddensity in Ghana,1922,1937, and 1958. Redrawnfroim nlaps in Gould, The Developiment ofthe Transportation PatterninGhana(seestarredfootnote in text),pp.104,107, and 109. This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES Tamale node on the GreatNorth Road to the node at Bole, which was just developing on the WesternTrunk Roadin 1922; Yendion the Eastern Trunk has been similarly linked. Lateralinterconnectionhas become intensifiedin the north, and the 21-40-mile shading nowcovers the entire zone between Bawku and Lawra. In the Kumasi area feeder development has continued, and the 21-40-mile shading blanketsthe Wenchi-Sunyani area to provide a fairly good network of interconnectionsbetween the Western Trunk and the Great NorthRoadinthezonewhere both converge onKumasi. Urban geographers will note the strong analogy to the process of interstitial filling between major radialroads converging on a centralbusinessdistrict. In 1958 the lateralinterconnection process is fairly well developed. Only a fewareas are still without road links, formerly inaccessibleareas having been tapped by the expanding road network. Anewseries of high-density nodes have developed since 1937 and already are reaching out toward one another. Marked examples occur in the north between Tamale, Yendi, and other northern population centers, and in the south in the developing and ex- tending nodes around Kumasi and east of the Volta River. It is clear from the regularity of the progression of the highway-density patterns that extrapolation of the density maps to some future date would be reasonable.In a sense the map sequence is a crude predictive device. For in- stance, the probability of an increasein road miles for any areabetween two nodes is greater than that for a comparable area elsewhere. In Nigeria a basically similar pattern had developed by 1953 (Fig. 8), with many oftheearlier nodes of highaccessibility inthesouth linking laterally toform an almost continuous high-density strip, broken onlyby the Niger Rivernear Onitsha. Lines of penetrationlinking the north and the south across the barren middle zone, a feature clearly brought out by the map, are relatively weakly developed, and the degree of lateral linkage is wellbelowthat of northern Ghana. Only the Kano and Zaria nodes, in areasof high agriculturalproduction and at the center of strong administra- tive webs, and the Jos node, at the center of the tin and columbium mineral complex, stand out as exceptions. Heavy rail competition, which resultedin severe restraintson long-haul trucking for many years, has clearly weakened the western road penetration lines, and the similarity to southwesternGhana is strong. Areas totally inaccessible by road are still numerous, particularly inthe barrenmiddle zone and along the periphery ofthe country. Tothe politicalgeographer the general weakness ofthe linkages betweenthe Eastern,Western, and Northern Regions will be of particular interest.There is, in fact, a clear visual impression that the general pattern of accessibility 513 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW by road in Nigeria in 1953 issimilar tothatofGhana in 1937-hardly sur- prising inviewofthemuch larger size of Nigeria, the longer distances, and thelower per capita taxbase fromwhichthe greater part ofroad develop- mentfunds mustcome. THEFOURTHPHASE:HIGH-PRIORITYLINKAGES The phase following the development ofa fairly complete and coherent networkisdifficult to identify, anda variety oflabels might be applied to it. Certainly themostmarkedcharacteristic ofthemostrecent phase inthe casesstudiedisthedominanceofroadoverrailroad.Acommontheme throughout the evolutionofthe transportation system in Ghana and Nigeria, andalsointheother examples studied, has beenthe steady rise intheim- portance ofroad traffic, whichfirst complements the railroad, thencom- petes with it, and finally overwhelmsit. However, theevidenceavailable seemstoindicatethatthisoccurs irrespective ofthe stage of transport de- velopment, and itis possible that a greater numberofroad penetration lines are now being built in areas whichwouldhave required rail penetration lines inthe past. Theidea ofa phase of high-prioritylinkages is based, somewhat weakly, ona logicalextrapolation oftheconcentration processes notedintheearlier stages of transport development inGhana and Nigeria, and is supported in partbyhighlygeneralized evidencefromareas with well-developed trans- portationsystems. Interiorcenters, intermediate nodes, and ports donot develop at pre- cisely the same rate. As someofthese centers grow more rapidly than others, theirfeedernetworksbecomeintensifiedandreach intothehinterlandsof nearby centers. Ultimately certaininteriorcentersand ports assert a geo- graphic dominanceoverthe entire country. This creates a disproportionately large demandfor transportation between them, andsincesome transport facilities already exist, the newdemand may take such formsas the widening ofroads orthe introductionof jet aircraft. In general,transport innovations are first applied tothese trunk routes.For example, intheUnitedStates the best passenger rates, schedules, and equipment are usually initiated over high- density routessuchasNew York-Chicago. In underdeveloped countries high-prioritylinkages wouldseem to be less likely to developalong an export trunk line than along a route connecting twocenters concerned in internal ex- change. Thereissomeweakevidencethat high-priority links may bede- veloping inthetwo study countries. High-density, short-haultraffic inthe vicinity of Lagos may be the forerunner ofa "mainstreet" betweencities of 514 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES NIGERIA ROAD DENSITY 1953 .MILESPER GRID CELLOF 283 SQUAREMILES iMore than 8021 to 40 61to 80::1 to 20 10oHU41to 60 0 ] FIG. 8-Road density in Nigeria, 1953. Compiled from sheets ofthe 1: 250,000 map series published by the Federal Survey Department, Lagos. the western part of the rail bifurcation.In Ghanathe heavy trafficflows focusing on Accra (flows that have tripledevery five years sincethe war) have virtually forcedthe authoritiesto bring the basicroad triangleup to first-classstandardsof alignment andsurface. RELATIONSHIPSBETWEENROADMILEAGESANDSELECTED PHENOMENA The lateral-interconnection phase ofthe ideal-typicalsequence isthe one that best depicts the currentextent of transportationdevelopment in most underdeveloped countries.This phase hasbeen accompaniedby a steady increasein the importance of motor vehicles, so thatat present the dominant transport characteristicof most underdeveloped countriesis the expansion of the roadnetwork.Closerexaminationof the roadnetworksof Ghanaand Nigeria affords deeperinsight into the factorsthat affectthe spatial diffu- sion ofroadsat a time when interconnectionis a prominent motive for 515 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW transportdevelopment. For example, howclose a relation is there between roads and population? Dosuch additionalfactors as environment, competi- tive transportation, and income have an effect onthe distributionofroads over and above the population effect? Attempts to answerthese questions are intheformofabasic regression model supplemented bycartographic analysis. In the basic regression model, road mileage within subregional units is treated as a dependent variable, population and area as the independent variables.6 The resultsof the regressionanalysis indicatea close relationship between the internal distributionofroad mileage and total population as corrected forthe differing areas of reporting units. Briefly, ithas beenfoundthat ina given unitroad mileage isin generalproportional tothe square root (ap- proximately) ofthe population timesthe square root (approximately) of thearea. Three-quarters oftheinternal spatial variationinroad mileage is associatedwiththesetwofactorsalone.7Thustoachieveafairfirst ap- proximation oftheinternal distributionofroad mileage at a givenpoint in time, welookfirst tothe population distribution. Effects ofdifficult terrain, unequal distributionof resources, rail competition, andthelikeonthedis- tributionofroads may be regarded as beingpartly subsumed by the popula- tionand area variables. Muchofthe impact ofthese factors onthe transpor- tation system is expressedthrough their relationship tothe population pattern. As expected, total population accounts formoreofthevariationintotal road mileage than area accounts for; inbothGhana and Nigeria itaccounts forabout 50 per cent.Theadditionofareaasan independent variable accounts for20 per centmore. Obviously, there is a greater needfortrans- portation for a givenpopulation in a large unit than in a small one. Although thedemandforroads generally reflects thedistributionofthe population, a large, sparsely settled unit will require a large per capita road investmentto be served at all. Thus the relative weights ofthe two independent variables, and 6 Sources for population figures were "Population Census of Nigeria, 1952-1953" (Lagos, 1954), and "The Gold Coast Census of Population, 1948: Report and Tables" (London and Accra, 1950); for road mileages, "Mobil Road Map of Nigeria," 1: 750,000 and 1: 500,000 (FederalSurvey Department, Lagos, 1957), and "Road Map ofthe Gold Coast," 1:500,000 (Department of Surveys, Accra, 1950). Only first- and second-classroads were included. No weighting system was applied. 7 For Ghana the regressionequation was log Yc = 0.1709+o.6285logX1 +0.4139logX2 or Yc = 1.482 X1 0.6285 X2 0.4139, with Yc theestimated highwaymileage, X1 thedistrict population inthou- sands, and X2 the district area. The r2 or explained variation was 0.75 or 75 per cent. For Nigeria the regression equation was log Yc =- 0.44771 +0.4458logX1 +0.4823log X2 or Y, = (Xl0i4458 X2 0'4823)/2.799. The explained variationin this casewas 81 per cent. In both casesthe particular form of the equation was the result of normalizing the data by means of log transformations. 516 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES the closenessof the correlation, areseento be significantly affected by varia- tions in the size of the reporting units; hencethe use of simplepopulation densitieswould have been deceptive inthat an understatementofroad- mileageexpectations for large,sparsely settledunitswould have resulted. On the other hand, it is not clearthat meaningmay be ascribedto the area variableas a separate factor.The problem of modifiableareal reporting units is, in general, a difficultone.8Internalvariationsin size of reporting units affectthe degree of apparent correlationbetweenvariables.Evenif the sizes of reporting unitswere uniform, differentcorrelationsand different regres- sion equations would be obtainedfor differentlevels of areal aggregation (a grid cell of to square milesas opposed to 100 square miles, for instance). In this case, it is best to regard the use of an areavariableas a meansof in- cluding the effectsof any internalvariationsin sizeof reporting unitson road mileagealong with any effectsof variationsin population. Thus it can be saidthat three-quarters of the variationin road mileageamong the arealsub- units in Ghanaand Nigeria is statistically associatedwith their combined variationsin population andsize. However,if the average sizeof the subunits weretobe significantly increasedor decreased, theamountof statistically "explained" variationwouldbeaffected. This relativelysimpleregression analysis may nowbetied directly tothe maps inan attempt touncoverfurther possible factorsthatseemtobe particularly relevanttothe development ofroad transportation. Inwhat parts ofGhanaand Nigeria doesthereseemtobea great dealofresidual variation? Where, inother words, doesthe population-areaequation seem to givesignificant overestimatesorunderestimates ofroad mileage?9 Exam- inationoftheresiduals maps for Ghana and Nigeriasuggests fiveadditional factors:hostile environment; rail competition; intermediate location; in- comeor degree of commercialization; and relationship tothe ideal-typical sequence. Precise quantification ofthese factors did notseem tobe warranted by the data. Therefore, a subjective examinationwas made ofthe relationship betweeneachofthefivefactors andthedistributionof regression residuals. 8 Some aspects of the problem are discussedin Arthur H. Robinson: The Necessity of Weighting Values in Correlation Analysis of Areal Data, AnnalsAssn. ofAmer. Geogrs., Vol. 46, 1956, pp. 233-236, and Otis DudleyDuncan, Ray P. Cuzzort, and Beverly Duncan: Statistical Geography: Problems in Analyzing Areal Data (Glencoe, Ill., 1961). 9 Theuse ofresiduals maps has been discussed by EdwinN.Thomas: Maps ofResidualsfrom Regression: Their Characteristicsand Uses in GeographicResearch, State Univ. of Iowa, Dept. of Geogr., [Publ.] No. 2, Iowa City[1960]. Examples ofthe use ofresiduals maps are Edward J. Taaffe: A Map Analysis ofAirline Competition, Part 2, Journ. of Air Law and Commerce, Vol. 25,1958, pp.402-427, and Peter R.Gould and Robert H. T.Smith: Method in Commodity Flow Studies, Australian Geogra- pher, Vol. 8, 1960-1962, pp. 73-77. 517 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICALREVIEW w.L.. .::i.:: t NEGATIVE : RESIDUALS 0Less than 10 miles 010-29 0 30-49 0 50-69 0 70-89 OMorethan 89 *More than 10% of the area hostile OBetween 5 and 10% of the area hostile FIGS.9 (left) ando1 (right).[Captionsopposite.] Ln :(:.:.:?'1:-`?'? .. . ': S^OtDi^. POSITIVE a .':::RESIDUALS 020406080 Miles ft ??: 518 ?(;????-.:?:?::ii ?? ????? ?......?::? ?" This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES In many instancesthe lack of dataresultedin highly generalized and arbitrary quantifications. HOSTILE ENVIRONMENT Considerationoftheeffects ofthe physical environment on highway mileagegives rise tosome interesting speculations. Thefirst finding is negative: namely, that the inclusion ofdifficult terraininthe analysis does notadd greatly toone's ability to predict the road mileage in a given unit once population and area have been considered. Although visual compari- son ofroad maps and topographic maps might suggest such a relationship, the effectsof sloping land seem already to have been discountedin individual units by the fact that they are thinly populated. Comparison of slope per- centages with regression residualsindicatedno significantrelationship. Thus there is no consistentevidence that a unit with a high percentage of sloping land has less road mileage than would be expected from its population and area as expressed inthe basic equation. It should be noted, however, that this statement toois conditioned by the size ofthe reporting units. Atthe scale of observation implied by the reporting units there was little evidence ofa separate effect of sloping land. But if reporting units were tobecome smaller, it is obvious that, at some scale, slope would have a marked effect onthe selection of specific routes irrespective of population. More refined slope measures might also have produced differentresultsat differentscales. Examination ofthe residuals maps (Figs. 9 and io)I0 does indicate that, 10 Onall the residuals maps circles are proportional tothe residual deviation from the regression formula. For example, on the positive residuals maps the large circles for Tumu, Ghana, and Abeokuta, Nigeria, indicate that they had considerably more highway mileage than wouldbe expected from the regression formula, which takes intoaccount population and area. Similarly, on the negative residuals maps the large circlesfor Kibi, Ghana, and Delta, Nigeria, indicatethat they had considerably less highway mileage than expected. In effect, then, these units showthedistribution ofthe variation in highway mileage attributableto factors other than population and area. FIG. 9-Hostileenvironment, Ghana.Estimateswere made ofthe areawithin a districtwhich would beclassifiedas swampy or noticeably dissected. Maps used were at the scale of 1:25o,ooo. Circles are graded insize according tothe differencesbetween actual road mileages and road mileages estimated from the equation Road mileageequals(1.482)(Population) (0.6285)times (Area) (0.4139). FIG.lo-Hostile environment, Nigeria. Estimatesweremade ofthe area withinadistrict which could be classifiedas swampy, noticeably dissectedor containing high mountains. Circles are graded in size according tothedifferencesbetween actual road mileages and road mileages estimated from the equation (Population) (.4458) times (Area) (o.4823) Road mileage = (2.799) 519 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW at the scaleof observation employed, two specific environmentalconditions seem to be relatedto the tendency for road mileage to be less thanwould be expected from a unit's population andarea."Thesearea very steep and consistent slope, suchas an escarpment, the trendof which is in general at right angles to the country'salignment of traffic, and the presence of ex- tremelyswampy land. Circleson the residuals maps have been shadedac- cording to the amountof "hostile"landin a particular unit, and sincethe presence of swamps or escarpments shouldreducethe road mileage associated with a givenpopulation and area, we should expect to findmostof theshaded circleson the negative residuals map. This proves to be the case.In Ghana fourteenofthe twenty districtswith more than 5 per cent of their land classifiedas hostile, andall six of the districtswith morethan o1 per cent, are on the negative residuals map. Low road-mileagefigures are most closely associatedwith the swampy landsin the Keta,Ada, andVoltaRiver districts. In Mpraeso North and Kibi thereis strong evidenceof the deterrenteffect of steep slopes where the prominentMampongescarpment has sharply curtailedthe development of feederroutes. In Nigeria low residualsareassociatedwith swampy landin the Colony and, in the Niger Delta,DeltaandRiversdistricts.An important difference, however, betweenthe swampy landsof Nigeria andGhanais thatin Nigeria the low residualsare associatednot only with an environmentunfavorable to road building but also with effectiveand long-established competitive water transportation.Waterwaycompetition is also reflectedinthe low residualsin Lowland, Wukari, Lafia,Tiv, and Idoma.These districtsare located along the middleand lower Benue, where waterway trafficis im- portant in view of the absenceof othereffectiveconnectionsto the zone of maximumeconomic activity. In Nigeria the only consistent relationship be- tween slope andlow road densityappears wherethereis a steepslope over a fairlylarge area, suchas an escarpmentlying acrossthe transportgrain, or wherethereis a large numberof steep volcanic ranges(the Cameroonsdis- trictsof Kumba-Victoria,Mamfe,Bamenda, and Adamawa). In the latter example, climate may alsohave played an important role. RAILROADCOMPETITION Logically, railroad competition could affectroad mileage either way. " For a considerationof other specific environmentalfeaturessee Benjamin E. Thomas: Transporta- tion and Physical Geography in West Africa (Prepared for the Human Environmentsin Central Africa Project, National Academy ofSciences-National Research Council, Divisionof Anthropology and Psychology [Department of Geography, University ofCalifornia, Los Angeles, 196o]). For example, Thomas documents the marked effect of seasonality on the utilization of roads in West Africa. 520 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES It couldreducethe needfor roads by providing an alternativeform of trans- portation; it could increasethe need for roads by promoting commercial production for interregionalexport. In the latter, or complementary, caseone might expect a proliferation of feederroadsfrom nodeson rail penetration lines. Although thereis some evidenceof the validity of both possibilities, the stronger evidenceseemsto be on the side of the positive effect.It is perhaps moreaccurateto say thatunitswith railroad mileage havemoreroad mileage thanwouldbe expected fromtheirareasand populations. Eitherthe railroaditself promotes feeder development, or both railandroadaretrans- port manifestationsof a high level of income, urbanization,or commer- cialization.Thereareinstanceswherelow road-mileagefigures areassociated with the presence of railroads, but this seems tobe where adeliberate governmentpolicy of protecting the railroadfrom competition hasbeenin effect.It is for the last reasonthat the residuals maps ofGhana (Fig. 11) are difficultto interpret: railroad competition has had sharply differentef- fectsin different parts of the country. Tarkwa's largenegative residualseems to be associatedwith the "economic gap"policy underwhich the building of importantthrough roads parallel to the westernline was forbiddenso as to preserve the railroadfrom competition.'2 In Kumasi, on the other hand, andto a smallerextent along the eastern line, the building of feedernetworks to the railroad appears to havehada positive effecton the residuals. In Nigeria(Fig. 12) thereis clearly no map evidencethat rail competi- tion reducesroad mileage below the level expected from population and area.The concentrationof high rail-mileagefigures on the positive residuals map indicatesthat the complementaryaspect ofthe relationship is much more evident.In Nigeria, however, it is difficultto separate the effectsbe- causeofthe more consistentdistributionofthe residualsinthe zone of maximumeconomic activity, wheresuchmeasuresas railroad mileage, com- mercial production, income, and degree of urbanizationwould also be ex- pected to be high.'3 INTERMEDIATE LOCATION In additionto the factors already discussed, the locationof a reporting unitwith respect to otherdistributions may haveconsiderable bearing on its road mileage. For example, a unit with a low populationdensity located 12 Gould, op. cit. [see starredfootnote above], pp. 44, 71, 102,106, andlo. I3 A multiple regression was also run using four independent variables (in logarithms): population, area, railway mileage, and waterway mileage. Theresults did notadd significantly tothe amount of variation inroad mileage statistically"explained" bypopulation and area. The regression coefficients for both railway and waterway mileage tested as statisticallyinsignificant. 521 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICALREVIEW - !'''': '',::.:::':.': .-::' -POSITIVE .OND.: RESIDUALS 020 406080 MilesI 0 Less than 10 miles 0 10-29 0 30-49 50-69 070-89 Morethan 89 * Rail competition present FIGS. 11and12-Rail competition, Ghanaand Nigeria. 522 '.::: '''' This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES FE COAST:::.:Q?:.': .!.{.'. ' NEGATIVE RESIDUALS 0 Less than 10 miles 010-29 0 30-49 O50-69 O 70-89 ( More than89 * Majorinterregional highway present FIGS. 13 and 14-Interregional highways, Ghana and Nigeria. 523 "' ....: ??? This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW betweentwo large citieswould tend to have more road mileage than one with the same density andareasurrounded by unitsof correspondingly low densities.To someextentthe importance of theareavariablein thebasic equa- tion is attributableto its inclusionof thiseffect.A large unitis more likely to includecentersbetweenwhich highways are needed.It is also more likely to includesome territory thatowes its road mileage to its position between two centersoutsidethe unit itself. The first attempt to treatthis effect systematically was in the form of a potentialmap. Thisconsistedin computing for all reporting unitsan index of the aggregateproximity of the restof the country'spopulationaccording to a gravity-model formulationin which the potential between any two units was regarded as being directlyproportional to the product of their populations and inverselyproportional to the distancebetweenthem.I4Thus a unitbetweentwo centerswould register a higherpotential thanan outlying unit. This shouldhave given a betterestimateof road mileage than the population and area figures. Such was not the case, however.The use of potentialfigures in a regressionanalysisgave a poorer correlationthaneither population andareaor population alone.Nor didit aidin the explanation of variationof highwaymileage when modifiedand treatedas an additional independent variable designed to isolatethe effectsof intermediatelocation. Examinationof the residuals maps indicatesthat the failureof this ap- parentlylogical index to provide abetter explanation than the straight population-areaequation was associatedwith the factthatthe intermediate- locationeffectwasnot widespread but seemedevident only where major in- terregional roadstraverseda unit. In other instancesthe areavariablehad apparently transmittedmuchof the effect.It shouldbe noted,however, that need for explicit treatmentof this effectbecomes progressivelygreater as the scaleof observationbecomescloser.The smallerthe reporting unit, the more likely it is thatroad mileage will be influenced by externaldistributions. On theresiduals maps of Ghana (Fig.13) theshadedresiduals represent the districtstraversed by the two largeinterregional roads.Thesedistrictsshould havemore mileage(from feedersas well asfromthe trunkroads themselves) thanwould be expected from their populations and areas.The mapspro- vide reasonablygood visualevidenceof the positive effectsof theseinter- regional roads.The string of positive residuals along the WesternTrunk Road fromKumasito Tumuis particularlystriking. The associationof posi- tive residualswith the GreatNorth Road is less spectacular. Thereis one 14 See JohnQ. StewartandWilliamWarntz: Macrogeography andSocial Science,Geogr.Rev., Vol. 48,1958,pp.167-184. 524 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORTINUNDERDEVELOPEDCOUNTRIES contradictory district (GonjaEast), and none of the residualsare more than half a standarderror above or belowthe regression estimate. The contrast among the northern districtsin this respect is interesting. Tumu has a very high residual; Navrongo and Frafrahave lowresiduals.The explanation seems tolieinthe population densities rather than inthe road mileages. Road mileage does not differ greatlyamong the three districts, but Navrongo and Frafraare much more densely populated than Tumu. Thus the negative residualsfor Navrongo and Frafra may be associatedwith a generally lower leveloffeeder-road development inthenorththan indistricts ofcor- respondingpopulation density in the south. In Nigeria (Fig. 14) major interregional roads are in general parallel to the railroads.There are, however, two areaswithout railroad mileage where the positive residualsseem tobe associatedwiththe presence of important interregional roads. Inboththeuse ofthe interregional designation may be legitimately questioned. One road, through thenortheasterndistricts of Bauchi, Gombe, Biu, Bornu, and Dikwa, is an extension from the zone ofmaximum rail and economic activity to Maiduguri and the Lake Chad area outside Nigeria. The traffic density on this road is relativelyhigh, and it represents one of the few caseswhere long-haul trucking is of major impor- tance in Nigeria. In thesouth tworoads serve as lateral interconnections between the two parts of Nigeria's bifurcatedrail pattern. They are classed as interregional roads because they carry heavy long-haul trafficand serve to link the Easternand Western Regions of a federated Nigeria. COMMERCIALIZATIONANDRELATIONTOTHEIDEAL-TYPICAL SEQUENCE It can beassumed that unusually productive units have relatively high incomes and therefore havemoreroad mileage than iscalled forinthe population-areaequation.Although the resultingrelationships are somewhat ambiguous anddifficult toisolate fromother factors, there isa general tendency for the more productive units to have more road mileage than ex- pected. Units focused on export agricultureappear tobe more important with respect to highways than units focused onmineral production. The maps are visually inconclusive, owingchiefly todifficultiesin obtaining data that realistically measured commercial production intheindividual units, and in separating commercial production from population that had already been consideredinthe regressionequation. For example, in Ghana (Fig. 15) it is probable that the highs aroundKumasiand in Ho and Krachiare associatedwith export agriculturalproduction. On the other hand, Tarkwa appears on the negative residuals map despite its large production for export, 525 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW because much ofthe production consists ofmineral ores (manganese and bauxite) hauled almost exclusively by rail. Thus, despite its relatively high commercialization, this district has less road mileage than wouldbeex- pected from its population and area. There seems also tobe an interesting time element in the relationbetween the cocoa districtsand road transporta- tion. Although the districtscited above show high residuals, the very new cocoadistricts (Sunyani, Sefwi, and Kumasi 4) show negative residuals. This may represent a tendency for transportationdevelopment to lag behind population in rapidly growing districts. In Nigeria (Fig. 16), as expected, the districtswitha large commercial production addlittletothe correspondence withthe positive residuals already noted onthe railroad and interregional-roadmaps. However, the commercialization maps do point up the persistentanomaly of the two im- portant northerndistrictsof Kano and Sokoto. These districts registernega- tive residuals despite a high degree ofcommercializationand the presence both of railroadsand of interregional roads. There is an interestinganalogy here tothe newcocoa districtsof Ghana, because Kano is also an area of rapid and recent economic expansion, and it, too, may well show a lag-and- lead pattern. The tendency for commercializationto be intercorrelatedwith popula- tion and road mileage, and tooccur within the general frame of the trans- port network, leads to a considerationof the relationbetween the residuals maps and the ideal-typicalsequence. As a rule, high residuals, representing large road mileage, are found inunits that also have large populations, a high degree of commercialization, and large railroad mileages. These units are usually in a zone ofmaximum activity, which includes the early pene- tration lines, the "main streets," and the majority ofthe interconnections. Outsidethis zone, toward the bordersof the country, transportationdevelop- ment seems weaker, as is evidenced by negative residuals. In Ghana the zone of maximum activity comprises the railroad triangle and some parts of the northern penetration lines. Districts peripheral to this zonethat exhibit weaker road development are thenewcocoa districts, the northern districtsof Navrongo and Frafra, and the southeast.Hoand Krachi are conspicuousexceptions, though this may be associatedwiththe political factorsmentioned earlier. In Nigeria there is a similarlystriking concentrationof positive residuals within the zone of maximum transportactivity, as would be expected from the ideal-typicalsequence. Most of the districtsin this zone also rate high in commercializationas wellas ineither rail mileage or interregional roads. 526 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORTINUNDERDEVELOPEDCOUNTRIES 0 Less than 10 miles 0'10-29 030-49 0 50-69 0 70-89 Morethan 89 * Relatively developed commercially FIGS. 15 and 6-Commercialization, Ghanaand Nigeria. Circleshavebeenshadedinthosedistrictswhich havebeen subjectively classifiedas beingrelatively urbanizedoras containing a relativelylarge amountof commercial agriculture. GEtUOGK. RtV.,UI .,I963 527 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTHEGEOGRAPHICAL REVIEW Conversely, the tendency forthe peripheral areas tohaveless road mileage thanwouldbe expected fromthe population-areaequation isevenmore markedthaninGhana.The onlymajorexception isthe northeast, inthe districtstraversed by thetrunk-roadconnectionto Maiduguri andthe LakeChad region. Acombinationoffactorsisalso responsible forthe negative residualsinthe south,southeast, andnorth.Alltheseareasare peripheral (with the possibleexception ofsomeinthe south), buthostile environmentand waterwaycompetition also effectively reduceroadmile- ages. InKanothe largenegative residual may beassociatedbothwith peripheral position andwiththe lag-and-leadpattern inwhich newly de- veloping areas may haveless transportation thantheir populations would seemtowarrant. THEANALYSISINPERSPECTIVE As population increases inan area, thedemandfor transportation isin- tensified; as new transport linesare builtintothe area, a greater population increaseis encouraged, which,in turn, callsforstillmore transportation. Ina sense, themodels artificiallyseparated thesetwoeffects:theideal- typicalsequence considered transportationexpansion as though itwere independent of population distribution; the regressions treated transporta- tionas though itwerecaused bypopulation. However, theresiduals maps provided intuitiveevidenceofthe lag-and-lead natureof transport de- velopment, aswascitedincases ofNorthern Nigeria andthenewcocoa districts inGhana.One mightpostulate a tendencythrough timeforthese alternate overexpansions anddeficitsofthe transportsystem tobecome gradually smalleruntila temporaryequilibrium isreached.A transport innovationorasuddendemandforanew penetration line, suchasthat occasioned by amineral discovery, couldthenreactivatethe process. This suggests thata possible avenueoffuture investigation of transportexpan- sionin underdeveloped countries might bethe application ofasimulation modelsuchas theMonteCarlo techniqueappliedby Torsten Hagerstrand inhis migration studies.'I The spatial evolutionofa transport and popula- tion pattern might besimulated through time byusing foreach stage inthe process asetof probabilitiesdependent onthe transport and population pattern ofthe precedingstage, thus bringing the essentially stochastic nature of transportation development intothemodel.Thedirectionoftheexten- sionofa transport linefroma givenpointmight bebased on probabilities 15 Torsten Hagerstrand: Innovationsf6rloppet ur korologisksynpunkt, Meddelanden fran Lunds Univ. Geogr.Instn., Avhandl. 25, 1953. 528 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and ConditionsTRANSPORT INUNDERDEVELOPED COUNTRIES derivedfrom factorssimilarto thosenoted in the discussionof penetration linesandthe Ghana highway-densitymaps. Finally, it shouldbe noted that the generalizations in this study are de- signed to provide an initial perspective on the expansion of transportation in underdeveloped countries.At the moment, it is probable that the varia- tions from the typicalsequence and the regressions are ofmore interest than their explicitapplication.'6 It is to be hoped that futurestudieswill bring aboutfundamental changes in the perspectivepresented here, at the same or a higher level of generalization. This may be accomplishedby field investigations,by the development of more useful transportationpa- rameters, and by the application of increasinglyrigorous methodsof analysis andmodelverification. i6 Cursory examinationof the Brazilian pattern, for instance, indicatesa continued viability of some of the scattered ports in coastal commerce, due in part to weak lateralinterconnection by land along the coast. Preliminary results from field investigations carriedon inthe state ofSao Paulo by Howard L. Gauthier,Jr., indicate a stronger emphasis on expansion of secondary roads toward the interior from railhead than onlateral interconnection during the period following the development of penetration lines. In former BritishEast Africa the political boundary between Kenya and Tanganyika has apparently restrictedlateral interconnection between two widelyseparated rail penetration lines. Population-area regressions run on road mileages for selectedSouth Americancountries by LawrenceA. Brown, graduate student at Northwestern University, also resulted in explained variations ofabout 80 per cent. The population exponent, however, ranged from 0.41 to 0.85 and the area exponent from 0.22to 0.37. 529 This content downloaded from 66.77.17.54 on Mon, 17 Feb 2014 03:51:12 AMAll use subject to JSTOR Terms and Conditions