A steady growth in traffic volumes makes it necessary to add traffic lanes to existing highways in order to increase current capacity. A possible measure may be to use the "extra lanes", the emergency lanes. In the study presented the objective was to calculate if and when an opening of these emergency lanes is economically justified. A calculation model was developed allowing the variation of several parameters: (1) investment costs; (2) maintenance costs; (3) user's costs such as journey time and operating costs); (4) costs for environmental damage; and (5) costs for accidents. One goal was to find specific thresholds for the AADT where a benefit would arise from the addition of an extra lane. An objective was also to find out whether it would be sufficient to add emergency bays or if it is necessary to build a continuous new emergency lane or if it would be enough to build a new non-continuous emergency lane. Each of these three alternatives is compared to the existing situation.
Samenvatting