Urban roads are some of the most dangerous. They have narrow shoulders, and it's easy for drivers to get distracted due to boredom or hazards. Highway shoulders are not very safe, and that's a problem that can lead to crashes.
Stopping on the Side of the Road
Take, for example, the idea of stopping on the side of the road. You need to stop because your vehicle is damaged. You get over as far as you can, but narrow shoulders aren't great for getting off the road completely. If your vehicle sticks out into the roadway and a driver isn't paying attention, then he or she could collide with your car.
Tow Trucks and Police Arrival
Even when a tow truck is at the scene or the police arrive, there's a risk that you could get into a crash because of others not paying attention or moving over into another lane. There are laws that require people to move over a lane when the police are active in an area or when a vehicle is disabled. Not everyone follows this rule, so don't take it for granted that you'll be safe outside, or inside, your vehicle when it's disabled.
As areas become more congested, the risk of crashes grows. For instance, a two-lane highway that needs to be expanded isn't prepared for three-lanes'-worth of traffic. Trying to have too many motorists on a road of an inadequate size puts everyone at risk. When drivers stop, they're less likely to have enough time to stop or room to get out of the way. If there's a disabled driver, there's an extremely high risk of being involved in a crash, since drivers can't move out of the way.
Urban roads pose a threat to the safety of those who use them. Dangerous drivers need to be held responsible if they cause a crash.
Source: Future Structure, "What Makes Urban Roads So Dangerous," Janet Moore, accessed March 30, 2018