Why does one collision cause such chaos across the city?
It seems astonishing that the closure of just one, short stretch of road can cause such chaos across an entire city.
But the collision on Dublin's M50 during the peak morning rush-hour yesterday did just that, affecting commuters across not only the capital but the Greater Dublin area, as a key section of the country's busiest road was closed.
Gardaí and the emergency services have an unenviable job. In cases of serious collisions, they must conduct a forensic examination of the crash site, which requires vehicles to be examined; the collection of evidence, including debris; measurement of skid marks if present; and other technical exercises.
Sources note this is because the collision site is treated like a crime scene. There is no suggestion that anything untoward occurred yesterday, but the procedures are that this forensic attention to detail is needed in the event of a further investigation.
That said, the M50 is three lanes wide. Did all three need to be closed? And why did it take more than five hours to re-open the road, and only after thousands of motorists were forced onto other, minor roads?
Despite being upgraded just five years ago, the M50 is at breaking point. Junctions are already over-burdened at peak times, and the road is in danger of returning to widespread gridlock.
But it's not just the city's ring road that's a worry. Every collision, whether in Donnybrook or Drumcondra, Fairview or Firhouse, appears to cause havoc during peak travelling times. There's simply too many cars and not enough road space.
We need more buses, trains and trams. More importantly, we need people to make the switch, unless we want crippling gridlock every time there's a collision in the city.