Secondary roads often suffer from diverted traffic trying to avoid congestion on major motorways. In this paper we study the traffic problems of a small town that is located parallel to a congested motorway and suffers from such diverted traffic (high local accident risks, local congestion and other nuisances). We assume that the motorway and the secondary road through the local town are under the jurisdiction of a different authority. A local government controls local accident risks and congestion using non-price measures such as speed bumps, traffic lights and explicit access restrictions for through traffic. A ‘federal’ government can control traffic levels on the motorway using tolls. We show the following results. First, competition between the federal and local authority leads to a Nash equilibrium where the toll is too high and there is too much traffic calming compared to the second-best social optimum. Second, if the local government uses traffic calming measures, imposing a federal toll on the main road is welfare-reducing, unless congestion on the main road is severe and accident risks and other traffic nuisances in the small town are unimportant. Third, traffic diverted from the main road to the local community gives the latter strong incentives to close the local road for through traffic, even when it is socially undesirable to do so. Fourth, if the access restriction only applies to through traffic by trucks, the conflict between federal and local authorities disappears: both will agree on restricting truck access. A numerical application using a two-link network between Leuven and Brussels (the highway and an alternative road passing through local communities) illustrates the theoretical results.

二级公路经常遭受交通改道的影响，试图避免主要高速公路上的交通拥堵。在本文中，我们研究了一个与拥挤的高速公路平行并遭受这种分流交通困扰的小镇的交通问题（局部事故风险高，局部拥堵和其他滋扰）。我们假设通过当地城镇的高速公路和次要道路在不同机构的管辖范围内。地方政府使用非价格措施（如减速带，交通信号灯和明确的通行限制）来控制当地的事故风险和交通拥堵。“联邦”政府可以使用通行费来控制高速公路上的交通流量。我们显示以下结果。第一的，联邦政府与地方政府之间的竞争导致了纳什均衡，纳什均衡的收费过高，与第二好的社会最优收费相比，交通平静得太多。第二，如果当地政府采取交通管制措施，除非在主要道路上拥堵严重且该小镇的事故风险和其他交通滋扰不重要，否则在主要道路上施加联邦通行费会降低福利。第三，从主要道路转移到当地社区的交通为后者提供了强大的动力，即使在社会上不希望这样做，也可以关闭当地道路以进行通行。第四，如果进出限制仅适用于通过卡车的通行，联邦和地方当局之间的冲突就不复存在了：双方都同意限制卡车进出。