How Effective?

The following statements present statistics that highlight the contribution that various motorway interventions have had towards road safety.


  • Typical reductions in ‘road usage costs’ resulting mainly from RTC savings from lighting are given as 20% for Motorways (Crabb, Beaumont & Webster, 2009).
  • The estimated effect of motorway lighting in preventing night-time RTCs in The Netherlands (during dry conditions) is 49%. The effect was reduced during wet or snowy conditions, and may not be comparable in other countries like Britain and Sweden (Wanvik, 2008).


  • New technologies such as section control (also known as average speed cameras) are being implemented in a number of countries, with early evaluations showing positive impacts on speed and crashes. In Austria, average speed cameras used over a section of motorway with a tunnel were associated with injury crash reductions of 33% over two years, with a cost-benefit of 1:5.3 (International Transport Forum, 2008).

Smart Motorways

  • Rush-hour lanes (similar to dynamic hard shoulders in the UK) are in operation in The Netherlands. Serious accidents decreased by 40% over the period 2004-2006 compared to 2001-2003, while the overall reduction on the whole motorway network was 30% (ETSC, 2008a).

Gaps in research

  • It was found that published research into motorway tunnels in the UK was particularly sparse. This may be due to there being fewer motorway tunnels in the UK compared with some European countries where RTCs in tunnels are more prevalent.

  • To date, there is only a limited amount of evaluation regarding the effectiveness of Smart motorways but research carried out by Highways England (2016) provides an initial overview of their effect on collision frequency. Based on the evaluation of two all lane running sections on the M25, Smart motorways appear to have reduced average journey times by between 2% and 9%. While reductions in the collision rates per unit distance were not significant, they were accompanied by increases in traffic volumes. In addition, monitoring of ‘Red X’ compliance found that, on average, 7% of vehicles were non-compliant. As Smart motorways become more prevalent, it is likely that the amount of research material in this area will increase.

  • More research is required on the midnight ‘switch off’ with respect to motorway lighting.

  • Date Added: 03 Apr 2012, 08:06 AM
  • Last Update: 07 Apr 2016, 02:13 PM