Motorways

Motorways

Summary:

This document has been compiled to highlight and summarise the safety aspects of motorways as a sub-category of roads, primarily in Great Britain.

  • Motorway travel is relatively safe: motorways carry about 21% of all traffic, but only account for 5% of fatalities and 5% of injured casualties (RRCGB, DfT, 2017); however, there are a number of key sub-topics relating to motorway safety which are currently subject to global debate.

  • The purpose of this document is to provide the reader with an overview of these sub-topics and provide material for further reading. Therefore, this synthesis has been summarised broadly into the following areas:

    • Speed on Motorways;

    • Driver fatigue/sleepiness on Motorways;

    • Inexperienced drivers on Motorways;

    • Motorway Lighting;

    • Motorway Tunnels; and,

    • Smart Motorways.

  • Excessive speed (i.e. speed in excess of the speed limit) on motorways is a major issue in many countries.  While the reasons drivers engage in speeding are varied and can relate to personal biases and environmental cues, the result is the same. That is, higher travel speeds increase the frequency and severity of collisions (e.g. Elvik, Christensen, Amundsen, 2004). In Germany, many of the motorways do not have speed limits or only have temporary speed limits imposed at peak running times. This is a major source of debate as, whilst German motorways are regarded as some of the most safely engineered roads, the country ranks only eighth lowest in terms of deaths per billion vehicle kilometres on motorways in Europe (European Transport Safety Council, 2008b). Decreasing traffic speed on motorways is likely to significantly reduce the rate of road traffic collisions (RTCs).

  • Motorways are notorious for providing a monotonous driving environment due to their form (e.g. few junctions, unidirectional flow, and minimal conflict) and the constantly flowing nature of the traffic on these roads (RoSPA, 2001). This means that fatigue or sleepiness in drivers on motorways may be more prevalent when compared to other road types. Drivers of Large Goods Vehicles (LGVs) may be more at risk from these effects than drivers of other vehicles due to the large distances involved whilst in transit, though little research has been identified to address this issue. Some research has shown that driving in the early hours of the morning and during the middle of the afternoon are the worst times for fatigue-related road traffic incidents (RTIs) (e.g. Horne & Reyner, 1995). This may be due to the lack of traffic on the roads at the time combined with the natural circadian rhythms of the human body.

  • Lighting on motorways is an issue that is currently under debate. Switching off lighting on motorways during the late night hours can save up to 20% on usage costs. Motorway lighting may or may not reduce the potential for night-time RTCs – some evidence shows that switching off street lights does not significantly affect collision rate – but it can be of assistance to the emergency services when attending an RTC.

  • The number of RTCs in motorway tunnels which result in KSI casualties is shown to be disproportionately high compared with the remainder of the motorway network in The Netherlands. However, it was shown that by introducing sectional control or average speed cameras in a motorway tunnel in Austria reduced RTIs by 33% over a two year period (International Transport Forum, 2008).

  • Smart Motorways have been developed in order to increase the capacity of a motorway without the need to construct extra lanes. This provides a cost-effective solution to motorways that suffer from congestion at peak times. The impact of Smart Motorways on road safety is not yet clear. Such schemes installed on the M42 in the UK and on motorways in The Netherlands suggested a decrease in the number of RTCs and fatalities. However, this work was early on in the development of this technology and further evidence relating to the safety implications of Smart Motorways is needed. More data on the behaviour of drivers using Smart Motorways will allow researchers to understand the safety benefits and likely effects on road users.

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  • Date Added: 03 Apr 2012, 08:06 AM
  • Last Update: 11 Dec 2017, 05:24 PM