Translated by Petter Gundersen, TØI
This relation can now be included in the cost-benefit analyses of new road projects, and consequently impact new motorways to be more profitable than the current calculation methodology.
A new TØI report has studied the driving comfort for different road types and expressed this through different time values for travel on the different roads. In general, motorists consider their time less expensive when driving on a good road compared to a bad road. They tend to drive a little longer or pay more if they can drive on a road with a high standard and high comfort compared to a road with low driving comfort.
The calculations in the report can be included in a cost-benefit analyses for road projects. This will provide a more accurate decision basis an can make road projects with a high standard more profitable.
When calculating time value factors for different road types, emphasis has been placed on both existing literature and results from surveys on the Arendal – Tvedestrand section.
In the report, the time value of an average road is set to factor 1, while better roads get a factor below 1 and worse roads a factor above 1.
The literature shows that the time value factor for a very poor and uneven road is often twice as high as for a good road with a smooth surface. This means that people are willing to accept twice as long travel time if the road has a very good standard compared to a poor standard road.
Surveys conducted on the Arendal – Tvedestrand section find significantly lower time value factors than in the literature. A modern four-lane road was built parallel to the old two-lane road. Using traffic counting points on both roads, the route choice for motorists was analysed. The ratio in time value between the new four-lane road and the old two-lane road is calculated to be 1.33.
The report has chosen to recommend time factors that are closer to the results from this case study than the general literature. A downward adjustment of the time value factors of 25 per cent has also been made to take into account that part of the benefit may be linked to higher traffic safety on the new road, and that this must be separated to avoid double counting in socio-economic analyzes.
The recommendations include that:
- Four-lane roads should have a 20 percent lower time value than the average
- Two-lane roads without a yellow center stripe have a 15 percent higher time value than the average
Table 1: Recommended time value factors for different road types, relative to the time value of a typical journey. To obtain the time value in Norwegian kroner, the factor must be multiplied by the time values from the new national valuation study.
The use of these results in the socio-economic analyses means that the profitability of a four-lane road increases compared with using the current calculation methodology.
The report emphasizes that the estimates are uncertain. The project was commissioned by Nye Veier.