Heavy lorries travelled further on German motorways in September than in August. The truck toll mileage index rose by 0.8% after adjustment for calendar and seasonal effects. Compared with September of the previous year, calendar-adjusted mileage increased by 2.5%. The index covers motorway distance travelled by toll-paying trucks with at least four axles, rather than all road traffic.
The indicator is available early and can provide clues about industrial activity. Components must reach factories and finished goods must travel to customers. Yet the relationship is not mechanical: a half-loaded lorry records the same mileage on a given route as a fully loaded one.
Changes in routes, supply chains or the balance between rail and road can also affect distance travelled. The monthly increase therefore identifies neither tonnes transported nor the value of the cargo. Comparing the mileage with production data released later is a practical way to see whether more movement on the roads coincided with higher factory output.