The present guidelines for the design of motorways in the Netherlands (the so-called ‘ROA’) were formulated in the 1980’s. Because of new insights and developments these guidelines are not complete or up to date anymore. Therefore, a beginning was made in 1996 with a revision of the ROA which led to a proposal of new guidelines for five new road cross sections of three traffic lane motorways. These new cross sections differed substantially from the standard cross section that is presently used of a three traffic lane motorway. The width of the traffic lanes in the proposed cross sections are (considerably) smaller than in the present cross section (2.50 m–3.35 m vs. 3.50 m in the present cross section), some cross sections have no emergency lane (there is always one in the present cross section), and for some cross sections overtaking is prohibited for heavy lorries. The proposed cross sections are not yet applied to the Dutch road network. Therefore, there is no information about the behaviour of drivers on such cross sections. In commission of the Transport Research Centre (AVV) of the Directorate-General of Public Works and Water Management of The Ministry of Transport, Public Works and Water Management a driver simulator study has been conducted by TNO Human Factors. The driver simulator study consisted of two experiments. In the first experiment driving for one hour on a new cross section was compared with driving for one hour on the standard cross section. In the second experiment driving behaviour on all new cross sections and the standard cross section was investigated. The results of the first experiment showed that driving on a small cross section (‘cross section 4’ with two traffic lanes of 3.10 m, a left traffic lane of 2.50 m, no emergency lane, overtaking by heavy lorries is allowed) lead to a higher risk than on the standard cross section. The standard deviation of the driving speed was considerably higher with cross section 4 than with the standard cross section and the duration of the crossing of the right lane markings was considerably longer with cross section 4 than with the standard cross section. There was no clear change in driving behaviour over time. These results strongly suggest that in its present form cross section 4 should not be applied. The results of the second experiment showed that driving on two new cross sections (cross section 1 and 2 with traffic lanes of 3.00 m or more) did not result in a higher risk than driving on the standard cross section. Driving on the other three new cross sections (cross section 3, 4, and 5 with a left traffic lane of 2.50 m) did result in a higher risk compared to the standard cross section. The latter conclusion was based on the time to line crossing of the right lane marking and the duration of the crossing of the right lane marking. The results of both experiments suggest that the cross sections 3, 4 and 5 should not be applied in their present form, while the cross sections 1 and 2 can be applied in their present form. Other considerations and arguments, however, should be used whether to apply cross section 1 or 2 or that both can be applied under different circumstances. (Author/publisher)
Abstract