Rijsimulatorstudie Keuzemarkering Fase 2: het toetsen van 3 nieuwe varianten [Driving simulator study "Optional road marking" phase 2: Testing 3 new conditions]

Purpose: Under contract with the Transport Research Centre of the Dutch Ministry of Transport, Public Works and Water Management, TNO Human Factors conducted a driving simulator study to assess the comprehensibility and driving behaviour on carriageways of motorways with optional road markings. On roads with optional road marking, an extra lane is created during rush hours by narrowing the lanes while keeping the emergency lane in tact. When optional road marking is used, the road markings for the situation in the non-rush hours (in this study 2 lanes) and the road markings for the situation in rush hours (3 lanes) are visible concurrently. Based on a prior feasibility study three new types of optional road marking were designed and tested in the driving simulator to see if, and if so which type of optional road marking would result in the required driving behaviour. Methods: Three groups of 40 subjects drove in the TNO driving simulator. Each group drove one type of optional road marking and subjects were not instructed on what to expect or how to behave. The idea was that subjects had to understand how to behave based on the road signs and the road marking solely. The 3-lane situation was supported by means of traffic signalling. In case of the 2-lane situation, nothing specific was shown above the driving lanes. The 3-ituation was designed in such a minimum way that it would not be necessary to support the 2-lane situation. Out of the three types tested, two types differed by different road signs above the lanes in the 3-lane situation. This way it was possible to see if a road sign with more information would also increase the comprehensibility and improve driving behaviour. Type 3 used the same type of road markings, but they were located differently in the carriageway without a recovery lane in either the 2-lane or the 3-lane situation. Subjects drove on roads with optional road marking, in the 2-lane and 3-lane situation. At the end of the experiment they drove some control rides with only one type of road marking begin present at a time. The traffic surrounding the subject was intense, and other cars always showed the right driving behaviour. Results and conclusions: The most stunning of the results is that there are hardly any differences between the types of optional road marking, not in subjective comprehensibility nor in shown behaviour, safety or in the questionnaires. Only the absolute lateral position on the road is somewhat different in Type 3 since these road markings are also placed on different locations. However, this does not result is better or safer behaviour. In the 2-lane situation, the right behaviour is shown in between 75% and 93% of the rides, but in the 3-lane situation this is (dependent on the lane one started the ride) between 38 and 80%. The 3-lane situation scores not too well under some conditions. It seems as if a relatively good comprehensibility of the 2-lane situation is compensated by a decrease in comprehensibility of the 3-lane situation. In some situations, people still drive according to the wrong road lay-out or even in between two road lay-outs. In the questionnaires, subjects indicate that the double road markings are confusing and one still misses information on how to behave. The principle of optional road marking is something so neroad marking is something so nerently it does not easily lead to a high comprehensibility in all situations without a specific instruction or information campaign. TNO recommends in a possible further step to confront drivers with the transitions in the road (this probably leads to a more comprehensible situation if people associate the situation with road works, in which also two road lay-outs are used simultaneously). Next to that information signs explaining the situation would need to be present in a next study in order to see if this additional information clarifies the situation. The recommendation is to leave Type 3 and not to include extra information about the road markings above the lanes. The left road marking for Type 1 would need to be interrupted. The conspicuity of the 3-lane situation would need to be increased slightly, possibly increasing the conspicuity of the 2-lane situation as well. It is recommended to always support the 2-lane situation with arrows, something that can also be a variable in a possible next step.