I wonder if any this applies to that experiment about adding obstacles in front of an exit speeding up exit times by slowing down individuals (especially in the case of an emergency - where sometimes the exits become blocked by the masses all trying to exit the same way - and perhaps even ignoring another route that would lead to a quicker exit)?

However the example have a road that takes 45 minutes regardless of how many drivers go through it, that is not very realistic is it. nowdays we have apps that can tell us in real time how long each path will take according to current traffic, and the time is never constant.

It's actually pretty realistic for very lightly congested roads. At those levels of congestion, the primary bottleneck is the distance and speed-limit. Marginally increased traffic will have minimal impact on travel time.

In contrast, for heavily congested roads, the primary bottleneck is the congestion itself. Hence, marginally increased traffic will have a proportional impact on travel time.

How does one car impact another? Wouldn't the drivers gravitate to the least congested/long road, and hence distribute across capacity?