Many visitors to this Blog have raised questions pertaining to vehicle damage incurred at construction areas and road works. This risk to vehicle damage is not confined to South Africa and extensive research has also been done in Europe to identify and address these concerns.
We would like to share some information added to the Arrive Alive website on the topic of Road Works and Road Safety:
Who are involved in road works crashes?
- In by far the most road works crashes only road users are involved. Crashes involving road workers form only a small part of all road works crashes (Hagenzieker, 1998).
- Although the number of casualties among road workers is limited, there are more work hazards for road workers than for industrial workers (Swuste & Heijer, 1999). Venema et al. (2008) also conclude that the risk of a fatal accident is probably higher for road workers than for the building trade in general.
- It has also been shown that half the road workers always or often feel unsafe during their working hours.
- A crash analysis using BRON data shows that freight traffic is relatively often involved in road works crashes. Overall, a freight vehicle is involved in 6% of the crashes; this is 14% for road works crashes. Other studies confirm this picture (Van Gent, 2007).
What are the causes of road works crashes?
- The international literature shows that road works crashes are relatively often rear-end crashes (Van Gent, 2007). Recent Dutch crash data confirm this: 31% of all rural road works crashes are rear-end crashes, in comparison with 15% of all rural crashes.
- Short headway distances and speeding play an important role in the occurrence of rear-end crashes.
- An extensive literature study of road user behaviour in the vicinity of road works was carried out in the European ARROWS project (ARROWS, 1999). The European PREVENT project has summarized the main findings and has studied more recent literature (PREVENT, 2003).
The most consistent finding is that:
- speeding is common at road works.
- The majority of drivers drive too fast when approaching road works.
- Drivers often do not reduce their speed until the traffic situation immediately in front of them urges them to do so (just before an abrupt change of circumstances) and consequently brake too hard.
- Although ‘fast’ drivers (with a high initial speed) have a relatively larger speed reduction than ‘slow’ drivers, their end speed still is higher.
- In addition, changing lanes is left rather late when a lane is closed off (Schuurman, 1991).
In a number of urban crashes, especially slow traffic enters a blocked road and then collides with works traffic, falls, or rides into a ditch (Janssen & Weijermars, to be published). Lack of clarity about the diversion and the lack of distinct marking of the work area seem to contribute to these crashes occurring.
What measures can be taken?
- Reducing the maximum speed is intended to ease the driving task.
- In addition it also reduces the risk of a crash and lessens its severity.
Supplementary measures like enforcement and dynamic speed information can be used to actually exact compliance.
Dynamic speed information is a measure which is used to measure the actual speed of each individual vehicle and communicate it to the driver (feedback). Research has shown that this causes drivers to lower their speed (Geluk et al., 2003).
In 2006, the Ministry of Transport started a new trial to reduce speed at road works. Road users were given immediate feedback on their speed, and at the same time their vehicle registration number was shown. This direct feedback seemed to have speed reduction as a result (AVV, 2007).
The lower a speed limit is, the more it is exceeded. A speed limit seems to be more acceptable and complied with when it is credible. Therefore, in 2005 the Dutch Ministry of Transport introduced new speed regulations during road works on motorways. The maximum speed is now 90 km/h and this is only lowered to 70 km/h if the lanes are narrow or if road workers work right next to the lanes without any barriers. When signaling is present above the road, speeds can be differentiated between lanes or for time of day.
Impact attenuators reduce the risk of crashes and in addition lessen their severity. Barriers lower the risk of a road user driving into the work area, but they increase the possibility of a crash with a rebounding vehicle. Physical barriers must therefore only be placed if they are absolutely necessary (Van Gent, 2007).