Danger of blow-ups – be careful on these highways
More than ten years ago, so-called blow-ups occurred on highways during extreme heat. Many of the critical spots have since been defused, but some sections remain dangerous. FOCUS online explains what car and motorcycle drivers need to know.
Imagine you're speeding down the highway at 180 km/h and suddenly the ground literally opens up. In 2013, there were around 80 such "blow-ups," in which the concrete cracked due to extreme heat. This poses a deadly risk, especially for motorcyclists, if they suddenly lose grip.
In June 2013, a motorcyclist rode over a half-meter-high bulge on the A93 near Abensberg (Lower Bavaria), crashed into the guardrail, and died at the scene. Since then, highway maintenance authorities have been particularly aware of the problem. "When air temperatures reach 28 degrees Celsius, warnings are issued. Above 30 degrees Celsius, speed limits of 80 km/h are imposed on vulnerable stretches," said a spokesperson for the Autobahn GmbH.
The problem only occurs during periods of extreme heat and only affects a few sections of highway, primarily those built in the 1970s and 1980s and featuring a thinner concrete surface than is common today (27 centimeters). The enormous volume of heavy goods traffic, especially in Germany as a transit country, means that the highways are under greater strain than predicted in the 1980s.
According to the Autobahn GmbH, the following sections, all located in Bavaria, are currently at risk of blow-ups:
- A3: Deggendorf motorway junction to Hengersberg junction
- A92: Oberschleißheim junction to Eching-Ost junction, Freising-Süd junction to Freising-Ost junction and Landshut-West junction to Dingolfing-Ost junction
- A93: Saalhaupt junction to Elsendorf junction
Heat speed limits have been in place on these sections since May:
- 120 km/h for cars
- 80 km/h for motorcyclists
In recent years, the concrete has been cut open at critical locations and the gaps filled with asphalt. While slight ripples can still occur in hot weather, these "seals" prevent the dreaded blow-up. "Although the damage is being repaired on an ongoing basis, a fundamental improvement in the road surface condition can only be achieved through thorough roadway reconstruction. Furthermore, the occurrence of heat damage in hot temperatures cannot be completely ruled out, despite the installation of asphalt cross-strips every 400 meters to relieve pressure on the concrete roadways," the Autobahn GmbH states.
In the long term, therefore, only a complete road renewal will help. On the A3 alone, over 100 km of road surface was replaced. On the A94, which runs from Munich to the east, heat-related speed limits are no longer necessary because the motorway was completely rebuilt between 2023 and 2024.
FOCUS
