All too often, where the rubber meets the road, it also meets the toad.
To the detriment of the latter. As if their cousins weren't in enough trouble - up to one-third of amphibian species worldwide are in danger of extinction - the toads used to suffer a high death-by-squishing rate on this stretch.
But now, a curious thing happens.
On rainy spring nights, patrols of a dozen or more volunteers, with flashlights and reflector vests, walk the Roxborough road, picking up hopsters and carrying them across the blacktop.
These aren't the only do-gooder toadies. Similar amphibian rescues occur from the country roads of Chester County to the green vales of England.
The Brits are so enamored that they've mapped 700 toad-crossings on Google Earth, and "toad patrols" regularly converge to handle the blitz.
At the Delaware Water Gap National Recreation Area, officials actually close a road to allow salamanders, frogs, and toads to cross unscathed.
It keeps things safe not just for the critters, but also for the parents and kids who show up to witness this slimy Serengeti of animals.
"It's a special moment," said spokeswoman Deb Nordeen.
Near Sumneytown, Montgomery County, science teacher Kathy Leber and some of her students walked Swamp Creek Road recently, carrying 68 salamanders to safer ground.
Then on Monday, she joined a group in northern Chester County that for several years has been safeguarding the spring hop across St. Peter's Road in North Coventry Township.
The scene resembles a kind of amphibian flash mob. Salamanders were already heading back to the woods, while "frogs and toads seemed to be going in both directions," Leber reported. "Their voices were an amazing cacophony of trills, grunts, and croaks."
To be sure, this can all get a tad nutty, drawing its share of smirks - and even angry responses from drivers.
But amphibians have been hit hard by humans. Only half of the wetlands that existed before Europeans arrived in America remain today.