Crashes at intersections are common and are characterized by the screeching of tires followed quickly by the brutal sound of metal hitting metal.  The front bumper of a car hits the back bumper of another or a speeding car crashes on the side of another that was making a left turn or yet a driver trying to change lanes finds himself on the direct path of another vehicle that was invisible.  Based on information from the National Safety Council 37,000 motor vehicle crashes occur every day on average in the US, with 41,480 deaths in 1998, representing an improvement when compared to 1972 (56,600 deaths) and this despite the dramatic increase of the number of vehicles and the miles driven.  Several factors are responsible for this improvement such as: seat belts, airbags, sturdier damage resistant cars, antiblock systems, improvements of the road network, strong measures against DUI, intensive law enforcement and other aspects of traffic safety.

However, vehicle drivers and their passengers continue to be exposed to the most dangerous of their undertakings on everyday life.  In 1997, 2.3 million Americans were seriously injured in crashes at a total cost to society of $200 million.  The types of crashes vary from the rollover of a single car on a remote rural area most probably late at night, to the familiar multivehicle pile-up at an interstate freeway due to bad weather or dense fog.  Very often, crashes occur at busy city intersections.  America's largest automobile insurance company, State Farm, has determined that one third of all crashes in effect happen at intersections and many of them are fatal.  San Francisco, is well known for many crashes due to red light violation.  Furthermore, the National Highway Traffic Safety Administration (NHTSA) reported in 1997, 8,571 fatal collisions at or near intersections, which amounted to 23% of all crashes in the US.  In Greece, from a total of 23,603 crashes in 1999, the 6,930 (29%) were attributed to driver error, 4,366 were due to violation of the right of way, 1,620 due to violation of traffic signs and 944 due to running a red light.  Most of these crashes probably occurred at intersections.

TYPES OF CRASHES: First, the most common intersection collision is the rear-ending of a vehicle by another due to the obligatory stop there.  Second, is the side-impact or collision at an angle which are more serious and third are the less common frontal collisions.  Causes of intersection crashes include: Running a red light, which together with ignoring the yield and stop signs are the most common causes of crashes in city traffic, in addition to inattention for incoming traffic when turning left or right.  However, most of the casualties in US are due to running a red light that accounts for 260,000 crashes, 121,000 injuries and over 800 deaths per year according to the Insurance Institute for Highway Safety.  Other collision causes are tailgating, speeding, which includes an attempt to forestall a red light by speeding up and bumping on another vehicle, whose driver anticipated a green light, and plain inattentiveness because the driver handles a cellular phone, the radio, eats, or is preoccupied.  In 1999, in Greece, 3,314 crashes occurred due to driver inattention and 1,121 because of tailgating.

FAULTY INTERSECTION: Sometimes there is something wrong with the intersection. For instance, when a motorist attempts a left turn and an oncoming car hits on the side.  The left turning driver might be blamed for failure to yield.  However, it might be that there is no left-turn signal and the driver took the chance of turning anyway, or if there is a left-turn signal it does not last long enough for most of the waiting motorists to make the turn, to the effect that one driver follows the one ahead of him into the intersection despite the fact that the light has already turned red.  It might also be that the driver's field of vision is inadequate so that a crash could be avoided with an oncoming car.  Canadian experts believe that 30% to 60% of collisions can be avoided or can be made less severe by improvements at intersections.  Dangerous intersections with a high rate of crashes should be studied by experts and special corrective measures should be taken based on the precise causes of accidents.

WHAT SHOULD BE DONE?  The Insurance Institute for Traffic Safety recommends the following: For the frequent running of red lights, red light cameras or the "photo radar" will be the answer.  The system includes the mounting of the camera on a pole and its wiring to a traffic signal, with the sensors buried into the intersection.  Any vehicle crossing the sensors on red light triggers the camera and a photo is produced showing the car, license plate, together with the date and time of the violation and the vehicle owner receives by mail a ticket with the photo.  Red light violations dropped 42% in Oxnard, California and 44% in Fairfax, VA., following introduction of red light cameras.  Violations dropped also at intersections adjacent to the ones with cameras. Other recommendations include:

• Improving traffic signal timing which can reduce rear-ending and brief red-in-all directions signals could prevent certain cross-traffic collisions.
• The adding of lanes for left-turn-only and permitting left turns only when traffic from the opposite direction is stopped.
• Improving the signal visibility such as by making them larger, brighter, or by installing an additional signal head.
• Give pedestrians time to start across intersections before the turning vehicles are allowed there.
• Replacing signal lights at intersections with a low traffic volume, with four-way stop signs. A similar program in Philadelphia reduced collisions by 24%.
• The conversion of two-way, with four-way stop signs, which has reduced crashes by a whooping 40% to 60% and injury collisions by 50% to 80%.
• Replacing conventional intersections with roundabouts--yield-at-entry traffic circles.  This method makes drivers to slow down and reduces the number of some types of crashes.
• Innovative use of "traffic calming" measures such as speed bumps, rumble strips and street narrowing (by using street-parking, planting and wider sidewalks) all of which induce drivers to use other streets that are better suited for high traffic volume.
• Adjusting the speed limits to be appropriate for a given street and neighborhood.
• The use of skid resistant pavement which reduces rear-end crashes, mainly with rain and snow.
• Improving lighting at intersections which reduces nighttime collisions.

EXAMPLES OF SUCCESS:  The evidence so far shows that such improvements at intersections are beneficial.  There have been two obvious success stories.  In Detroit, three intersections were upgraded as above and crashes were reduced 39% to 48% and the injury collisions were cut down 34% to 70%.  A program involving six intersections in British Columbia reduced the rear-end crashes by 40%.

WHAT CAN THE DRIVERS DO. The issue of Traffic Safety cannot be left only to the experts and to the authorities.

• You the driver should cooperate with perseverance and tenacity in order to avoid crashes at intersections.  Do not speed at intersections, look at you left and right and pay attention to other drivers who are trying to beat the signal change.
• You should learn by heart the rules of the road concerning intersections and follow them.
• Do not follow other vehicles very closely (tailgate). They might stop suddenly. Always watch out for pedestrians and cyclists. Give a turning signal before you turn or change lanes and be sure that you are in the right lane before you signal your intention to turn.
• Do not make a left turn when you see oncoming traffic except when you are sure that you can turn safely.  Do not ignore signals or signs that prohibit turns and do not turn right if it is unsafe.  Do not even attempt to beat signal changes because another driver in the cross street might try it ahead of you.  Always watch out for motorcycles and emergency vehicles.
• When waiting at intersection to make a turn keep your wheels straight to avoid being propelled to another lane, when hit from behind and never change lanes at an intersection.
• Avoid entering an intersection when traffic is backed up on the other side, because might be unable to leave the intersection before the light change and might be stuck in the middle.
• With rain or snow, be careful of the slippery pavement and reduce your speed so that it will be easier to stop if you have to.

SUMMARY: Every intersection is a dangerous place day or night, due to the constant flow of traffic.  Prudent drivers come into contact with other drivers who are, in a hurry, or plain clumsy, aggressive, careless, inpatient, distracted, sleepy or drowsy, DUI, and some of them might have an appointment with the guillotine at the intersection.  Knowing and respecting the right of way are crucial for survival.  Intensive driver training is the key so that everybody is following the same rules of survival.  Respect for pedestrians and the handicapped is paramount.  Intersections with a high rate of accidents need special study.  A reduction of the number of aggressive drivers and intelligent modification and functional adjustment of intersections reduce the number of accidents.  For the young, aged 18 to 25 and for the elderly the intersection can be a killer.  For young males the culprit is testosterone and for the elderly is the aging process.  The issue of Traffic Safety should be quickly brought up to a Science.  The Rules of the Road should be strictly enforced.  This is the only way that the menace of dangerous intersections will be abolished.

1-30-2001



Sources:

-The New Wellness Encyclopedia ,UC Berkeley, Health Letter Associates,1995.
-State Farm Online, Intersection Backgrounder, Intersection Crashes.
-Accelerating Save Driving Behavior, Occupational Health and Safety, March 1999.
-Fatal Crash Risk for Older Drivers at Intersections, Accid. Anal. and Prev..30:151,1998.
 

*/ (Em) Professor of Medicine and Biological Chemistry UC Davis School of Medicine, President Traffic Safety Task-Force for Greece and Science Advisor to the Commissioner Highway Patrol (CHP) State of California.
**/ Economist, Executive Boeing Corporation, Seattle WA., Task-Force Program Manager.
***/(Ret) Captain California Highway Patrol, Task-Force VICE-CHAIRMAN.
****/Deputy Commissioner, California Highway Patrol, Task-Force CHAIRMAN.

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