Geometric Design and Road Surface: Impacts on Motorcycle Safety International Conference on Transport and Road Research, Mombasa, Kenya, 15 th to 17 March 2016
Introduction Findings of AFCAP-funded research on five rural roads in three districts of Tanzania: Almost 90% of motorised vehicles are motorcycles Injury rates among motorcycle drivers are very high, almost one per driver per year in some areas Amputations, broken bones, head injuries Primary contributory factor is road user behaviour Road design and condition also contribute
Example of a crash The motorcycle was travelling from Talawandato Bago, with no passengers. The driver was travelling fast on the left Parallel Concrete Strip close to Kiembevillage. At the junction where the strip ended and a gravel section began, the driver hit a pothole that had been created due to erosion. He lost control, came off the road and struck a tree. He was unconscious for approximately one hour. No other vehicle was involved.
Example of a crash Near Ludigavillage the motorcycle driver encountered a car coming in the opposite direction. The road was narrow and the car did not give him the right of way, so the motorcycle driver was forced to squeeze to the side of the road where the road surface was muddy and slippery from the rain that was falling. The motorcycle slid on the slippery surface, and the driver lost control and fell off on the side of the road. The front light of the motorcycle broke, and the driver suffered severe pain in his chest.
IRAT Road Safety Programme IRAT: Improving Rural Access in Tanzania (DFID-funded) GBP 25m: physical works to upgrade rural roads Development of rural road safety programme for local government. Two components: Behaviour change Engineering
Engineering Component Input to development of Manual for the Provision of Low Volume Roads Important, but limited space available Development of materials and/or training for District Engineers More comprehensive
Geometric Design Width: If roads are too narrow, motorcycles are forced off
Roads need to be wide enough for a motorcycle to pass a 4-wheeled vehicle safely Minimum 3.8m, exc. shoulder: Car = 2.0m. Motorcycle = 1.0m Clearance between vehicles = 0.4m Clearance to either shoulder = 0.2m
Shoulders or at least strengthened edges are very important: Minimum width of 0.5m At-grade with the main carriageway, without a significant drop between the carriageway and the shoulder Free from loose material Free from oversize material Free from vegetation Regularly maintained
Speed The problem is not always highspeed, it s inappropriate speed for the road conditions Speed is a concern for local communities
Speed humps are a key part of the solution
Forgiving roadsides: Avoid steep side-slopes (flatter than 1:4) Avoid deep side-drains close to carriageway, and ensure drains are clearly visible Regularly clear vegetation that obstructs vision Remove large trees and rocks, especially on outside of curves Use guard-rails to protect immovable hazards Clearly protect and demarcate bridges and drifts signs, marker posts, bollards, guard-rails
Road signs: Warning signs and marker posts: Significant bends Pedestrians and animals Narrow carriageways Speed humps Temporary signs: Roadworks, Potholes, Loose stones, Edge drops Regulatory signs: Speed limits Height, width and weight
Road Surfaces Gravel. Asphalt. Concrete. Blocks. Good surfaces allow high speeds, so speed control and forgiving roadsides are essential Surface defects that may cause discomfort for passengers of 4-wheeled vehicles can cause crash risk for motorcycles
Gravel: Remove oversize stones Asphalt: Avoid overly smooth surfaces Concrete: Scour to provide grip, avoid excessive roughness Blocks: Risk of severe injury with hand-packed stones
Parallel Concrete Strips: Edge drops. High speeds. Narrow carriageways Good lines of sight. Good shoulders. Maintenance
Transition between different surface types Angle ends down. Regular maintenance
Next Steps Pilots of working with District Engineers to implement recommendations Development of a document for District Engineers, detailing all recommendations Development of a training programmefor District Engineers Also working on the BehaviourChange component
Thank you for your attention www.research4cap.org Join the ReCAP Group on LinkedIn Tom Bishop and George Malekela, Amend tbishop@amend.org gmalekela@amend.org