Will planned increase in speed limit lead to problems on Czech motorways?

Most European countries seem to agree on a speed limit of 130 km/hour or less on their motorways. The Czech Republic, however, may soon become the only country in Europe where the limit would be 160 km/hour. But that higher speed limit seems to be popular mainly among some Czech politicians - experts are less enthusiastic about the idea.

The Czech Ministry of Transportation is going to come up with a bill in the summer which, if passed, would enable drivers to go at a speed of 160 km/hour on certain parts of Czech motorways. What would be the effects of such a speed limit? I spoke with one of the country's leading experts in the field Professor Frantisek Lehovec from the Department of Road Construction at the Czech Technical University.

"The flow of traffic which moves along a certain route brings with it a certain risk of crashes, because it involves various manoeuvres, such as overtaking and returning to the lane. As soon as we start to influence the homogeneity of the flow of traffic by making a huge difference between the slowest and the fastest cars possible, the number of dangerous situations will sharply increase. So, the homogeneity of the flow of traffic is absolutely crucial, as far as the level of road traffic risk is concerned."

This seems to take the wind out of the ministry's sails, as the homogeneity of the flow of traffic is one of its key arguments in favour of a higher speed limit.

Professor Lehovec points to a recent British study which dealt with the effect of higher speed limits on traffic risk. It found that every kilometer of average speed increases the probability of a traffic accident by 5%. He is also convinced that the capacity of Czech motorways would decrease if a higher speed limit was allowed, whereas even now some motorways are already over-burdened. A higher noise level and higher amounts of emissions are other minuses of the ministry's proposal.

"A higher speed limit brings with it an increased amount of emissions. And since the relation between the two is not linear but geometric, it means that even if the speed is increased only a little, it leads to a considerable increase in the production of emissions. But this is not the only problem that the higher speed limit would cause. There is also noise pollution, which would be a burden to the close surroundings of the motorways where the speed limit was increased."

Czech motorways, like those in almost all countries in Europe, were designed with the intention that the speed limit would not exceed 120 km/hour. There are some sections where a higher speed than the current 130 km/hour would be technically possible. But the overall negative effects on the environment and increased traffic risk will undoubtedly make it a topic of heated discussions in the months to come.