(Updated September 28, 2018)
Thanks to all who have visited this website during the last eleven years; especially those who completed the questionnaire. The Data you have supplied has been analyzed and results are presented in this website.
Have you ever wondered …
1. What is the safest speed to travel in traffic and how can you find it? Click here to learn how to choose the safest speed.
2. Why the great majority of motorists exceed speed limits?
3. What can be done about motorists who
o impede others in the left-hand lane,
o do not signal soon enough,
o follow too closely,
o drive slower in left-hand lanes, forcing others to pass on the right,
AMERICA’S MARVELOUS HIGHWAYS
The nation’s roadways are marvels of design and construction. Wide freeways cross the United States and local streets are generally well maintained.
Travel on our highways is very safe—much safer than ever before. The probability of dying in an automobile crash has decreased 75% during the last fifty years.
According to the National Highway Traffic Safety Administration (NHTSA), 2008 was a hallmark year when highway deaths fell below 40,000 for the first time, declining 9.3% from 41,259 to 37,423. In 2009, fatalities further decreased by 9.7% to 33,808. This trend continued in 2010 with an additional 3% decrease to 32,788. 2011 saw a further 0.94% decrease to 32,479 and deaths increased by 3.33% to 33561 in 2012. The overall five year decrease is 18.7%, a truly remarkable and welcome development.
Nonetheless, while the great majority of motorists are careful, responsible drivers and highway design and construction have steadily improved, traffic laws and enforcement practices not kept pace. This creates safety problems and adds unnecessary stress to the driving experience.
Let’s take a detailed look at each of the driving practices in the questionnaire:
IMPEDING TRAFFIC
Slow drivers in the left-hand lane often cause vehicles to accumulate behind them. This congestion may spread to right-hand lanes creating a cluster of closely spaced vehicles across all lanes—a ripe environment for safety problems:
- When an emergency vehicle is held back by a slow vehicle in the left lane or is trapped in a cluster, it may be delayed in reaching a crash site or medical facility. This means that injury crashes or other medical emergencies may convert to fatalities because emergency vehicles did not arrive in time to render life-saving aid or were delayed while traveling to a medical facility.
- Impatient, aggressive, or foolhardy drivers jockey from lane to lane trying to find their way through an impedance-induced cluster. They endanger themselves and others by squeezing into small spaces and following too closely.
TURN SIGNAL TIMING
Signaling before beginning a turning or lane-changing maneuver may be far more important than most drivers realize. The Society of Automotive Engineers has published a report indicating that proper signaling could reduce rear end crashes by 90%, yet common practice is to signal at the same time, or even after beginning a maneuver. Signaling is merely a meaningless gesture when given too late for others to respond.
FOLLOWING DISTANCE
It should be obvious that following so closely that there is not time to respond to a slowing vehicle increases the risk of a crash. Changing lanes is also more hazardous when space between vehicles is restricted by drivers who follow too closely.
IMPROPER LANE USAGE
When slower drivers allow faster drivers to pass on both sides, the probability of a rear-end collision doubles and smooth traffic flow is disrupted.
SPEED OF TRAFFIC IN HOV LANES
Vehicles with two or more occupants may be permitted to use HOV (high occupancy vehicle) lanes. These lanes are provided to encourage car-pooling and produce faster, more efficient travel when other lanes are congested.
Unfortunately, HOV lanes may attract slow drivers who happen to have another passenger in their vehicle. Traffic backs up behind such drivers, frustrating following motorists and reducing highway capacity.
Drivers who prefer to drive slower than the normal speed of traffic should use a general purpose lane and allow the HOV lane to fulfill its purpose of increasing capacity.
COORDINATING LAWS AND LIMITING LAWS
Before discussing speed limits, let’s pause for a moment to note that the purpose of traffic laws dealing with the first four items in the questionnaire are "coordinating laws". They encourage motorists to coordinate their vehicles with others in orderly, safe traffic flow.
Note also that coordinating laws involve simple acts of courtesy. Those who violate them forgo opportunities to show courtesy and respect to other drivers and run the risk of offending them. No one gains by going against these reasonable requirements.
In contrast, the speed limit law is a limiting law that restricts the speed drivers are permitted to choose. Note that speed limit laws are not necessarily related to courtesy. A person who chooses to drive faster or slower than others may be as courteous as any other driver.
A principle of good traffic management is that limiting laws must not interfere with coordinating laws. For example, obedience to unrealistically low speed limits may impede traffic and disrupt what would otherwise be safer traffic flow.
ACHIEVING VOLUNTARY COMPLIANCE TO COORDINATING LAWS
A characteristic of human nature, the risk-reward principle, may be the basis for achieving voluntary compliance to coordinating laws.
In most cases, we must take a risk in order to enjoy a reward. Common sense dictates that we will only take a risk if we believe a reward will follow that is worth more than the risk. On the other hand, if we believe the reward would not be worth the risk, or there would be no reward at all, it makes no sense to take the risk.
Note that motorists have nothing to gain by violating coordinating laws—there is no reward. On the contrary, others may consider them rude and inconsiderate.
Therefore, the key to achieving voluntary compliance to coordinating laws may be to expose drivers to a significant risk of being penalized for disobedience by vigorously enforcing these laws.
Present enforcement policy seems to concentrate on speed limits with little attention to coordinating laws, possibly forgoing opportunities to significantly improve safety on our highways.
Achieving voluntary compliance to coordinating laws may be as simple as:
- Providing fair, enforceable, coordinating laws, and
- Concentrating enough enforcement effort on these laws so that drivers recognize a significant risk of being cited for violations.
ACHIEVING VOLUNTARY COMPLIANCE TO SPEED LIMITS
In contrast to coordinating laws, the risk-reward principle may encourage disobedience of unrealistic speed limit laws.
As long as it is safe to do so, motorists may benefit by driving faster than unrealistic speed limits: They may save time or avoid the tedium of driving at an unnecessarily slow speed. Therefore, when motorists believe that the risk of receiving a speeding ticket is smaller than the benefit of exceeding a speed limit, the risk-reward principle may encourage violations.
Also, there is no underlying relationship between speed and courtesy. A reasonable driver who chooses to drive faster or slower than others may be as courteous as any other driver. As shown on the next page, data collected from the questionnaire indicates that motorists may not object to speed limit violations as much as they object to coordinating law violations.
By following well established scientific principles, authorized agencies can create realistic speed limits that will be voluntarily obeyed by the great majority. See the Fair, Legal Speed Limits page in this website.
SCIENTIFIC SPEED LIMITS CAN HELP TO COORDINATE TRAFFIC
When a speed limit is set scientifically, it notifies drivers of the safest speed at that location under favorable conditions. The more drivers who choose this speed, or speeds approaching it, the better coordinated and safer the overall traffic flow becomes.
SURVEY RESULTS
An analysis of data collected from the questionnaire is shown on the next page