Congestion leads to several economic costs of which the increase of travel time is the most important. Others are costs due to unreliability of travel times and additional fuel costs due to higher fuel consumption under stop-and-go conditions. It is estimated that the economic losses of congestion account for 2% of total GDP in EU of which 30% caused by trucks. The problem of congestion is increasing and is projected that the related cost to society increase by 50% until 2050.

For logistics operations, congestion increases not only the travel time, but also leads to a reduced reliability of travel times, which in turn reduces productivity of operations within factories, warehouses and shops. The value of time and value of reliability is not unique for all traffic units, it varies significantly, depending on many different parameters. Generally, on average trucks have a higher value than cars, and bigger trucks than smaller trucks, but the average value alone is not a sufficient parameter describing the whole traffic, as the variation between the cheapest and most expensive traffic units can be very high (Figure 1).

One strategy to reduce the economic losses of congestion is to separate normal traffic and priority traffic onto different lanes, i.e. to prioritize freight traffic which in average have a highest value of time than passenger cars. The cost benefits of these ‘truck-only lanes’ depend on several factors such as traffic volume, truck percentage and value of time conditions.