Vehicle occupant protection has come a long way, but drivers and passengers continue to be injured due to the sheer physical forces that can be involved in a crash. Humans are not designed to resist the g-forces created in a severe impact, and the shell of a car can be breached by a big enough vehicle (e.g. a lorry) or point-loading in the right place (i.e. items entering the cabin through windows or pushing bodywork unevenly). This can cause many different types of injury.
This is the most common injury in a nose-to-tail collision. A vehicle hits another vehicle from behind. The passengers in the front vehicle have an impact which pushes their bodies forward, but their heads and necks snap backwards.
Modern cars have whiplash-reducing headrests, but rear-seat passengers often don’t have the same luxury. Taller passengers may be too tall for the support provided by the headrest.
Whiplash can cause a sore or stiff neck and shoulders, trapped nerves in the neck and shoulders, numbness in the neck, loss of range of motion when turning the head and headaches.
Wrist and hand injuries
If you watch a racing driver have a crash, they will remove their hands from the wheel just before impact. An impact can cause wrist fractures. If the front wheels are turned during the crash, this force is transmitted through the steering wheel which can move so violently that it can break or dislocate thumbs.
As hands and wrists are full of many smaller bones, restoring the complete range of movement and strength in the joints can take some time; it may never return to normal.
Vehicle crashes often smash the glass which then showers the vehicle occupants. This creates a cut hazard, if not from the initial impact, at least when trying to get out of the vehicle.
An impact into part of the interior of the car can also result in cuts and bruises, some of which can cause permanent scarring.
Bruises and soft tissue damage
While vehicle interiors are made as soft as possible, there are still many hard surfaces which can cause serious bruising. In a rollover situation, it is almost impossible not to hit against hard surfaces such as the windows. Airbags may inflate, but they only inflate once and then deflate, providing much less protection.
Head, face and eye injuries
The airbag will help reduce the severity of the first impact, but airbags only inflate once, so any subsequent impacts won’t be cushioned as much. In a side impact, the head will be jolted sideways and can hit the side windows. This is also bad for the neck and shoulders.
If glass shards are also in the vehicle, these can cause facial injuries.
The g-force from an impact can cause a detached retina. This results in reduced peripheral vision, blurred vision, flashes of light in one or both eyes, or a shadow over your vision and requires an operation to repair.
Your eyesight may not then meet the requirement for driving if it can’t be fixed adequately.
Massive deceleration forces slam the brain into the front of the skull causing a concussion or even serious, long-term brain injury.
Rib and sternum injuries
Rapid deceleration while being held in by a seatbelt can cause broken ribs or a broken sternum. Ribs can also be damaged by secondary impacts and by items hitting the back of the seats.
These injuries take a long time to heal and are debilitating due to them being painful at every breath for weeks.
Internal organ injuries
If ribs are broken, the sharp edges of the bone can tear major blood vessels leading to massive internal bleeding. It can also damage internal organs, as can the rapid deceleration.
Lap belts can cause injuries to the lower torso.
Hyperextension of the neck and back can result in spinal injuries. These can cause anything up to paralysis.
Leg and foot injuries
Like the hands, the feet contain many small bones. The pedals can cause foot injuries. A collapsing steering column can cause knee injuries (although most newer vehicles have drive-by-wire rather than a steering column, and knee airbags).
In a frontal impact, the engine can be pushed towards the cabin, bending the firewall and reducing the space in the footwell, causing crush injuries.
If the driver or passenger slides under the seatbelt (‘submarining’), this can create a bigger likelihood of leg and foot injuries; most vehicles have anti-submarining seats.
Leg and foot injuries can take a long time to return to full capacity.
Airbags have an explosive charge in them to make them inflate fast enough. This can cause superficial burns to hands, arms and face. These are unlikely to result in scarring.
Some crashes can result in a fire in the vehicle which can cause serious burns.
A serious crash can cause ongoing anxiety, driving phobias and over-cautious behaviour on the road which is then dangerous for other drivers. Counselling can help alleviate this.