Pet And Car Collisions Many Times End Badly7 min read

 In Cats, Dogs, Emergency Medicine



One of the most frequently seen injuries in animal emergency clinics across the country are pet and car collisions.  They are so common that veterinarians coast to coast use medical shorthand on medical records to describe them.  The term HBC, written on medical charts, means “hit by car”.  Any animal or person hit by a car can be severely injured. Huge, buck deer can meet their demise after having been struck head on by a vehicle.  Due to their small size dogs and cats are no match for the size and force of any car driving down the road. That force is explained by the law of physics- F=ma.  That is the force of something is equal to its weight multiplied by its speed (acceleration).  That force is daunting when compared to a tiny 10 pound cat.

Pet and car collisions rarely occur on major interstates.  They have limited access that keeps dogs and cats off of them.  Most pets are injured on city, suburban or rural roads that have easy access.  Rural roads are often poorly lit at night.  The majority of pet and car collisions involve intact male dogs; particularly retrievers that need a tremendous amount of exercise. Intrinsically, dogs and cats do not know that cars can injure them.  A female enters estrous (heat) and the male chases after her, oblivious to passing cars.

Cats are another story.  One of the distinguishing features of cats is their uncanny ability to avoid disasters due to their lightning fast speed and nimbleness. Add their small size to that mix and you have a creature that is acrobatic at times.  When cats get hit by a car they escape with just a nick to one of their whiskers or they get banged up badly.  Many cat/car accidents result in fractured pelvises or internal injuries.

Do we include motorcycles in this mix?  I rode for many years in Ohio.  It was a true joy except when I saw a dog coming at me while driving.  Dogs are ultra intelligent animals.  They know how to triangulate where I was on the road and where I would be in a few seconds.  They then tried to intercept me at that second position.  In this case hitting a dog would injure the animal but would throw the rider from his bike.  That is not good.  The trick?  Slow down, shift down and accelerate rapidly when the animal approaches.

The number one reason why pet and car collisions occur is not using leashes or some other appropriate type of containment system such as good fencing.  Allowing cats to roam is the number one reason why that species is injured.  Keeping cats indoors is the only foolproof method of preventing car accidents.




Many pet and car collisions are fatal to animals.  However, many are not!  This is due to how a pet and car come together at that fateful moment.  The degree of injury to an animal often depends upon the angle that the pet and car collisions occur. Pets that chase after cars, such as herding dogs, may simply bounce off of the vehicle after having been struck.  That causes an injury as well as injuries suffered due to rolling along the asphalt road.  This latter injury is know as “road rash” or worse.  Head on collisions are almost always fatal due to massive internal bleeding that causes immediate death.

One of the most under reported pet and car collisions are those that occur right on the owner’s property!  This usually involves a car parked in the driveway.  A dog or cat will seek refuge from the hot sun by hiding under the vehicle.  This hiding is often done behind the rear wheels.  This is bad.  The owner puts the vehicle in reverse and backs over the animal.  This also happens to young children.  A lot of what happens to animals in these situations is chalked up simply to luck.  I had a case where an owner backed up over the lower back of a Cocker Spaniel.  I told the owner to rush the animal to my hospital.  I couldn’t believe my eyes!  The dog walked into my office and into the exam room with nary a limp.  You could see the perpendicular, black tire marks as they crossed the dog’s lower back!  No internal injuries.  No fractures.  No spinal injuries.  No nothing.  It was simply amazing.




It is impossible to describe all the variations and injuries that veterinarians treat on a day to day basis but many injuries can be put into groups.  Each accident victim is different.  No two injuries are alike.  No two individuals are alike.  Add to that predisposing medical factors such as chronic disease or arthritis and you can see why medicine is not easy.  Each animal is treated on an individual basis.

  • Road Burn-  This occurs after an animal bounces off of a vehicle and rolls on asphalt.  The results are huge abrasions that can expose underlying muscle tissues.  These are treated medically and surgically.  The big problem with these lesions is infection.
  • Fractures-  This is a very common outcome of pet and car collisions.  The majority of fractures occur on:  the forelimbs, hindlimbs and pelvis.  Spinal fractures are also seen with corresponding neurological damage to the body.
  • Abdominal And Chest Injuries-  These injuries are some of the most life threatening of all.  Trauma from the car accident results in bleeding into the chest cavity causing respiratory distress and or a ruptured spleen that fills the abdominal contents with blood.  All of this crashes the animal’s blood pressure.  Emergency surgery is the way to go here.
  • Lacerations-  These occur after striking sharp objects on a vehicle or from some other source during the collision.  In the absence of internal injuries these lesions are cleaned and sutured together, with or without drains.
  • Joint Injuries- Animals may suffer a joint injury by having it come into contact with a car during contact.  One of the most commonly injured joints is the knee (stifle) joint.   The knee joint also happens to be the most complex of all joints in any mammalian body.  Injuries to the:  menisci, cruciate and collateral ligaments plus tendons are common.  Some animals may just suffer an acute swelling of the joint capsule that can be medically treated.  Otherwise many of the above injuries are treated surgically.
  • Neurological-  These are some of the most difficult cases to treat because no one knows the eventual outcome.  I frequently got asked right after an accident if the animal could ever walk again on X limb.  I always said that I don’t know at that moment.  The most common neurological injury is radial nerve paralysis of the forelimbs.  An animal can walk but putting pressure on the limb while walking causes the carpus (wrist joint) to knuckle over.  Head injuries are common.  Swelling of the brain is the big concern here plus the possibility of seizure activity in the future.  The worst of the worst neurological injuries are a complete severing of the spinal column.

There are times after a car accident where dogs just simply walk away from an accident.  These situations are few but gratifying.  As pet owners it is crucial that you know where to take your pet if an accident occurs. Some veterinarians refer all after hour emergencies to a specialty practice.  Just find out where to go and keep in mind that the closer the clinic is to your home the better.

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