IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

AQUAPLANING AND TRAFFIC SAFETY ON

HIGH SPEED ROADS

Juš Žnidaršič, Project manager, Asfalteks d.o.o.

Decreasing the water film thickness with

diagonal grooving

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

0. CONTENT

1. Background and Introduction

2. Objectives

3. Solutions

4. Solution Implementation

5. Evaluation of Results and Next Steps

6. Acknowledgements

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

1. Introduction

- High number of accidents are caused by water present on the road surface

- Water film aquaplaning effect lost of adhension

- Higher risk of aquaplaning effect in cross slope transitions

- Diagonal grooving for succesfful drainage and increased adhension

1. Introduction: water film

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

2. Objectives

- Increasing road safety by preventing water film on the road surface

- Increasing drainage in the solid screwing zone

- Increasing adhension between pneumatic tire of the vehicle and road surface

- Time and cost efficent technology to achieve above objectives

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

3. Solutions

- Permeable asphalt surfacing, without additional sub-base drainage

- Surface grooving

- Diagonal grooving

- One of the most sufficent methods for reducing aquaplaning in areas of

insufficient roadway drainage

- Water film in cross slope transitions permeates the structure of the

surface into which a system of grooves has been cut

- Roadway grooving : Mechanically cutting grooves into the roadway

surfacing

3.1. DIAGONAL GROOVING

3.1. DIAGONAL GROOVING

- Cutting grooves into the roadway surfacing

(roadway grooving)

- The water film is absorbed into the system of grooves below the

contact surface between the road and the tires

3.1. DIAGONAL GROOVING

- Distribution of sistem of

grooves on the road

3.1. DIAGONAL GROOVING

- Diagonal grooving on the

bridge

3.1. DIAGONAL GROOVING

4. SOLUTION IMPLEMENTATION – Roadway grooving model

- Angle of grooves:

45 º

- Distance of bands:

2 – 5 m

- Width of bands:

30 cm

- Depth of grooves:

5 – 6 mm

4. SOLUTION IMPLEMENTATION

The durability of grooving in asphalt pavements:

- asphalt type

- asphalt composition

- type of stone aggregate in the asphalt

- traffic load

4. SOLUTION IMPLEMENTATION

The durability of grooving in asphalt pavements:

- stone mastic asphalt (SMA): at least four years (up to six)

The durability of grooving in concrete pavements is much longer

4. SOLUTION IMPLEMENTATION

4.1. Important details for successful drainage

- Denivelation of asphalt

4.1. Important details for successful drainage

- Solution for denivelation

of asphalt

4.1. Important details for successful drainage

- Insuficient maintainance

of road and drainage

sistem

4.1. Important details for successful drainage

- Grooves filled with

material

4.2. Accident analysis on Croatian highways

- Three grooved sections of the Rijeka-Zagreb motorway have been

analysed.

- The following diagrams show the number of road accidents before and

after grooving.

4.2. Accident analysis on Croatian highways

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4.2. Accident analysis on Croatian highways

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4.2. Accident analysis on Croatian highways

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acc

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- According to the analysis, the average number of accidents was 3.53

accidents per year before grooving and 0.67 accidents per year after

grooving, i.e. the number of accidents has dropped by 81%.

4.2. Accident analysis on Croatian highways

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

5. EVALUATION OF RESULTS AND NEXT STEPS

- Diagonal roadway grooving proved to be a simple and efficient way to reduce

aquaplaning effect on roads

- Time (500m in 8-9 hours) and cost efficent

- Further development of grooving technology for faster implementation

- Road analysis before and after grooving showed that grooving reduced the

number of road accidents in critical areas by as much as 80%.

IRF Brazil Conference. October 26th, 2011. Iguazu Falls, Brazil

Juš Žnidaršič, Project manager

E: jus.znidarsic@asfalteks.si

Asfalteks d.o.o.

Letališka 33,

1000 Ljubljana,

Slovenia, EU

6. ACKNOWLEDGEMENTS