Thirty-eight bridges in the greater St. Louis area are just "a step or two from being closed" due to deterioration, according to the Missouri Department of Transportation.
They are among the nearly 600 bridges statewide that officials say are currently rated in poor to serious condition, but aren't funded in the state's five-year plan for improvements.
But during that same five-year timeframe, MoDOT told the state transportation commission Tuesday, the total number of bridges in critical shape statewide could top 1,000. Within a decade, that number could rise to 1,500 bridges.
The report comes as expected funding declines for highway and bridge construction will limit the ability to replace these deteriorating bridges, said state bridge engineer Dennis Heckman.
"We have an aging bridge population and with the diminishing funds that we have to replace the bad bridges, we're only going to have enough money to do another 15 bridges a year," Heckman said. "So we're just going to keep falling deeper into this hole, unless something changes on the funding side."
With most designed to last 50 to 75 years, the average age of the state's bridges is 45 years old, Heckman said. Most of the greater St. Louis area's problem bridges were built in the 1960s and '70s, though eight date back to the '30s and '40s. That includes one bridge in St. Louis County built in 1928.
Though Heckman said "a lot of progress" has been made on the St. Louis area's bridges, he said the lack of funding has forced MoDOT to prioritize work on bridges that get the most use.
"We decided to place our limited resources only on the primary system, but even then there's 100 of those bridges in the primary route, so we're really just trying to play catchup and it's really falling farther behind," he said.
Already Missouri has closed five bridges outside the St. Louis area. MoDOT officials say once a bridge is rated to be critical, it is closed.
"Public safety is our number one issue," he said. "The rule of thumb is, if I won't let my wife or kids drive across the bridge, then it's closed."
But closing a bridge interferes with people's mobility and economic development, Heckman said.
"It impacts school bus routes, mail delivery, emergency services, fire trucks and ambulances - that starts to come into play with weight restrictions- so it just starts to disrupt people’s lives," he said. "From the economic development side, getting to and from work and getting materials, it all starts to get impacted as we close bridges."
Heckman said if people are concerned about funding for bridge repairs and replacements, they should contact their state legislators.
Ray Howze in Jefferson City contributed to this report.