The age of the roadway is what contributes to making it more dangerous. Decades old roadways are weren’t constructed for the amounts of traffic, types of vehicles, speeds we see now.
Every driver has the responsibility to drive no faster than conditions safely permit. That’s the Basic Speed Law. It doesn’t matter how fast cars can go relative to how fast they could when the road was built. The entire responsibility lies on the driver and not on the road.
As for volume of traffic, overcapacity usually results in lower collision rates with the possible exception of rear-enders.
No road is “dangerous” by reason of not accommodating reckless driving.