During the most recent measurements, in 2022, 2.6% of the Dutch drivers were under the influence of alcohol during weekend nights, which amounts to almost double the lowest percentage of alcohol offenders measured (1.4% in 2017).

In general, crash risk is higher in bad weather than in good weather. Adverse weather conditions are mainly rain, snow/hail, fog, strong winds, slipperiness, low sun and high temperatures.

Wrong-way driving crashes are infrequent, but their outcome is often serious. Most wrong-way driving crashes occur when drivers inadvertently enter a motorway exit or when drivers turn around on a motorway.

Traffic congestion occurs when traffic demand exceeds road capacity, or when an incident such as a traffic crash, a vehicle breakdown occurs or temporary roadworks take place, all of which temporarily reduce capacity and restrict traffic flow. Congestion crashes mainly occur at the tail end of a traffic jam. There, the speed of the traffic flow decreases sharply, which coincides with frequent and hard braking, and with a high risk of rear-end crashes.

It will probably take at least several decades for completely self-driving vehicles to become commercially available, if they ever will. Yet, vehicles in which part of the driving task is automated, for example automated braking, accelerating and steering, are already available.

If the average speed on a road increases, crash risk also increases, as does the risk of a serious outcome. This is true in general terms, but more so when motorised vehicles crash with unprotected road users, such as pedestrians, cyclists and (light) moped riders. Furthermore, speed differences between vehicles at any one time or place are related to a higher crash risk. Drivers that maintain a speed that is higher than the average speed on that road run a higher crash risk; drivers that maintain a speed that is lower than average do not.

Risky road user behaviour is behaviour that adversely affects road safety, such as driving under the influence of alcohol, drugs or medicines, speeding, inappropriate speed, distracted or fatigued driving, red light negation, and failure to use or misuse means of protection (motorcycle or moped helmet, seatbelt). Younger road users more often display risky behaviour than older road users, and men more often than women.

The mobile phone is symbolic of ‘distraction in traffic’. But apart from mobile phone calls, texting, or listening to music, many drivers, cyclists and pedestrians are occupied with all sorts of other activities that may distract them. Examples are: operating the navigation system, eating, drinking, talking to passengers or daydreaming.

From 2009 to 2018, an annual average of 80 road deaths were attributable to crashes with trucks and 67 road deaths to crashes with delivery vans. Casualty numbers are higher among crash opponents than among occupants of trucks or delivery vans. The fatality rate among crash opponents is higher when they crash into a truck or delivery van than when they crash into a car. The fatality rate among occupants of a truck or delivery van, however, is lower than among car occupants. Among the occupants of trucks or delivery vans, most fatalities occurred on provincial road and on national roads.

Driving under the influence of drugs or impairing medicines reduces fitness to drive[i] and increases crash risk. Drugs have a numbing, stimulating or mind-altering effect on the brain, or a combination of these effects, which impair traffic task performance. For drug use in traffic, we (unfortunately) have to rely on research dating back to 2011.