When a construction fire damaged Pittsburgh's Liberty Bridge last month, the Pennsylvania Department of Transportation closed it for 24 days to do repairs.
So a lot of trucks now weigh too much to drive over the bridge.
That hasn't stopped drivers from doing it anyway. Last month, several drivers reported to PennDOT that heavy-looking trucks were being driven over the bridge.
PennDOT sprung into action, adding weight limit signs and working with state police, who are stationed at checkpoints near both sides of the bridge, to step up enforcement, Triblive.com reports.
The thing is, weight limits like this one aren't unique. Pennsylvania has nearly 6,000 structurally deficient bridges, and many of them are weight-restricted. In some places, the limits can mean trucks have to take longer routes, costing time and money.
In other cities, the situation can force emergency vehicles like fire trucks to choose between taking long detours and crossing a bridge they might be weakening. Both actions potentially put the public at risk.
Fines for an overweight vehicle crossing a bridge can be thousands of dollars. But it's hard to catch a driver in the act. Most weight-restricted bridges don't have police stationed at either end, like the Liberty Bridge now does. That means the decision over whether to cross comes down to an individual's discretion, and violations will rarely be noticed.
Inspectors monitor the state's bridges at least once every two years. PennDOT says that if a bridge is unsafe, it'll be closed, and that weight restrictions are intended to slow deterioration.