When dealing with the duality of mobility and safety, speed is one of the main factors causing deaths, so this is the reason why speed is one of the most studied topics related to road safety. The main objective of this research was to identify the aspects that modulate the speed-accidents relation. Specifically, the frequency and reasons why drivers speed. On the other hand, it was also considered the perception of drivers regarding the probability of penalty, the penalties imposed, and their severity. Finally, drivers¿ opinion on the effectiveness of such penalty in order to change speeding behavior was also studied. A sample of 1,100 Spanish drivers over 14 years old and having any kind of driving license was used. The results showed that approximately the third part of drivers always or sometimes sped. Among the specific reasons, the hurry, not having noticed, that the limits are too low or that the conditions allow doing so were the most frequent. Likewise, drivers considered as limited the probability of being caught. Finally, more than half of the drivers considered that the penalty they received was appropriate. Moreover, half of the drivers that received a penalty claimed that they changed their speeding habits as a result of such penalty. Drivers who speed are completely aware of the fact that they are breaking the traffic rules. Their speeding behavior is intentional in 80% of the cases. They are not aware of the risks of speeding since they justified their behavior by saying the speed limits are too low, the conditions on the roads allow doing so, or that it was a habit
