In dense vehicular traffic cars often drive at close distances,
they form clusters or platoons. Within these platoons, time headways
are observed, which are often even shorter than the reaction time
of the drivers - a situation which is potentially dangerous. 

Here we propose a simple dynamical model for a platoon undergoing
emergency braking, which takes into account the individual variations
for the reaction time and braking capacities.
We illustrate our approach on real traffic data and use our results
in order to compare the impact of different possible regulations
(speed limit, minimum headway).