When speed goes down, stars go up!

© Evonik Resource Efficiency GmbH

#SlowDown for Safe Roads

The relationship between speed and safety is clear. The higher the speed, the greater the likelihood of a crash, the more energy in any impact and the greater the serverity of a crash. 

The star rating of a road provides a simple, objective, research-based assessment of the safety of a road for all road users. 5-star is the safest and 1-star is the least safe. As speeds go down on a road, the star ratings go up. For each incremental improvement in star rating the cost of fatal and seriously injured crashes is typically reduced by 33-50% (OECD, 2016).

graphic_safe_roads.png

Source: OECD, 2016

 

 

© Asian Development Bank

Speed, road design and star rating

What speed do you need to travel on each road type to ensure a 3-star or better experience? What road features should you include in a road design to provide a 3-star or better experience for all road users? Explore the relationship between speeds, road design and star ratings in the images below.

 

Urban roads Rural roads Motorways

Urban Roads

#SlowDown on high-standard urban roads to be #3StarOrBetter for pedestrians*

When basic features like footpaths, pedestrian fencing, and safe speed-managed crossings are in place a road can be 5-star for pedestrians at low-speeds. Speed management and traffic calming that keeps speeds at or below 50 km/h can ensure a 4-star or better experience for pedestrians.

high_standard_urban.png speedometer urban good

 


#SlowDown more on low-standard urban roads to be #3StarOrBetter for pedestrians*

When footpaths are ineffective or non-existent and crossings are absent or do not effectively slow traffic the risk to pedestrians is hard to manage. Speeds must be 40 km/h or less to provide a 3-star or better experience for pedestrians.

low_standard_urban.png  speedometer urban poor

 

* Intersections have not been included in examples above. Intersections add an extra level of road safety risk and extra care is required at all intersections. Roundabouts that manage speeds effectively through the intersection and grade separated interchanges are safest.

Rural Roads

#SlowDown on high-standard rural roads to be #3StarOrBetter for vehicle occupants*

When a rural road has basic separation of oncoming traffic with central hatching or wide centerlines and when roadsides are relatively free of hazards, the road is straight and well line-marked and intersections are limited higher speeds can be managed. 3-star or better performance can still be achieved at speeds up to 110 km/h for vehicle occupants. 

high_standard_rural.png speedometer rural good
 

 


#SlowDown more on low-standard rural roads to be #3StarOrBetter for vehicle occupants*

When a rural road is curvy, there is no separation of high speed traffic, road condition and signage is poor and roadsides are full of hazards that can kill, the risk to vehicle occupants is hard to manage. Speeds must be 50km/h or below to ensure a 3-star or better performance.

low_standard_rural.png speedometer rural poor
 

* Intersections have not been included in examples above. Intersections add an extra level of road safety risk and extra care is required at all intersections. Roundabouts that manage speeds effectively through the intersection and grade separated interchanges are safest.

Motorways

#SlowDown on high-standard motorways to be #3StarOrBetter for vehicle occupants*

When a high-standard motorway is provided higher speeds can be managed.  Concrete barriers separating oncoming traffic, wire rope barriers protecting roadside hazards, wide shoulders, good line-marking and street lighting all make a big difference to safety.  4-star or better performance can still be achieved at speeds up to 120km/h. 

high_standard_motorways.png speedometer motorway good

 


#SlowDown more on low-standard motorways to be #3StarOrBetter for vehicle occupants*

When a motorway is not designed well speeds must be effectively managed with enforcement. Medians that allow vehicle-cross over or head-on crashes; roadsides with steep drainage channels, embankments or trees and poles; narrow shoulders and poor signage and line-marking all reduce safety. 3-star or better performance is only possible at speeds less than 70km/h or less.

low_standard_motorways.png speedometer motorway poor


* Intersections have not been included in examples above. Intersections add an extra level of road safety risk and extra care is required at all intersections. Roundabouts that manage speeds effectively through the intersection and grade separated interchanges are safest.

"For Iloilo’s avid cyclists, any reason is a good one to ride. Here they ride to celebrate women".

 

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© Eric Barbosa Jr.

More information

To explore the impact of speed on the full range of road types and the associated star ratings for pedestrians, cyclists, motorcyclists and vehicle occupants try the Star Rating Demonstrator. For more information on 3-star or better roads visit Irap. Note: Star rating targets used by road agencies worldwide relate to average results over longer sections of road. 

 

iRAP 3-Star or Better Star Rating Demonstrator

Learn about the other solutions:

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