Knott News Are You Following Too Closely?

Are You Following Too Closely?
by Ben T. Railsback, M.S., P.E.
Many drivers do not know or understand the recommended distance for following the vehicle in front of them. The Colorado Driver’s Handbook states that “The driver of a motor vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicles and the traffic upon and the condition of the highway.” The practical advice given to drivers in the Handbook to achieve a “reasonable and prudent” distance is the “3 Second Rule.” When the vehicle in front of you passes a landmark, shadow on the roadway, or other reference point, your vehicle should not pass the same reference point until 3 seconds has elapsed. The “3 Second Rule” actually refers to a time rather than a specific following distance. Since the rule refers to time rather than distance, higher traffic speeds will result in longer following distances.

Adequate following distance is important for two reasons. The first and obvious reason is to prevent your vehicle from rear ending the vehicle in front of you. Secondly, a safe following distance will also give the driver and vehicle behind you a greater margin of safety. When there is adequate space in front of your vehicle, you can slow down at moderate deceleration rates rather than an aggressive rate, allowing the vehicles behind you to slow down comfortably.

Many accident reconstruction experts use a perception and reaction time (for an emergency braking event) of 1.5 seconds. If you are following closer than 1.5 seconds to the vehicle in front of your vehicle, you may not be able to react in time to avoid a collision. A “3 Second Rule” following distance also allows for additional time in the event that your eyes are momentarily diverted from the roadway if you are adjusting your radio, or glancing away from the roadway. Historically, drivers were taught to follow one car length behind the vehicle in front of them for every 10 miles per hour (mph) of traveling speed. The practice of following at one car length for every 10 mph may not create sufficient following distance. Some drivers have difficulty estimating distance well and may have difficulty visualizing car lengths. For example, at 60 mph the one car length practice would result in a following distance of approximately 84 feet for a driver who believes that the average car is 14 feet long while it would result in a following distance of 108 feet for a driver who estimates that the average vehicle is 18 feet long. However, if the following driver has a brake response perception and reaction time of 1.5 seconds and is traveling 60 mph, the vehicle will cover 132 feet during the perception and reaction time before the driver has applied the brakes, a distance greater than 84 or 108 feet which may result in a collision. Therefore, most drivers are no longer trained according to this practice. Proper following distance for heavy trucks (such as an 18-wheeler) is even more complicated. The Colorado Commercial Driver License Handbook states that “…you need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add one second for safety.” For example a 70 foot long truck and trailer should follow the vehicle ahead at a distance of 7 seconds below 40 mph. Above 40 mph the Handbook recommends adding 1 second for a following distance of 8 seconds.

Knott Lab is Celebrating Our 30th Year in Business!
Knott Lab is proud to announce our 30th anniversary since the company was formed. Over that time, Knott Lab has been fortunate to work with the nation’s best lawyers and highest profile cases. Please look for our special 30th Anniversary Newsletter in the upcoming months!

Company News
Paul Bennett, P.E., CBIE, Promoted to Director of Civil/Structural Engineering Knott Laboratory, LLC is very pleased to announce that Paul Bennett, P.E., CBIE has been promoted to Director of the Civil/Structural Engineering Department. Paul joined Knott Lab in May 2009 as a Senior Engineer. Paul has over 10 years of experience as a Civil/Structural Engineer, is a licensed civil engineer in eight states, is a certified building inspection engineer and he expects to receive his M.S. degree in Civil Engineering, with an emphasis in structures, in 2012. Prior to joining Knott Lab, Paul was also a general contractor, building higher end, single family mountain homes. In the past two years at Knott Laboratory, Paul has inspected and reported on over 250 structures with damages due to construction defects and weather, among other causes.

Richard M. Ziernicki, Ph.D., P.E. presents “Effective Use of the Latest Technology in Reconstructing Trucking Accidents” at the National Interstate Trucking Summit sponsored by the Association of Plaintiff Interstate Trucking Lawyers of America (APITLA) and The National Trial Lawyers on September 15-17, 2011 in St. Louis, MO.

Paul Bennett, P.E., CBIE presents “Ethics and the Expert Engineer: Why Doesn’t My Guy Agree with Your Guy?” to the Construction Law Section of the State Bar of Nevada. On Tuesday, September 13, 2011, Mr. Bennett presents in Las Vegas, NV at the University of Las Vegas. On Wednesday, September 14, 2011, Mr. Bennett presents in Reno, NV at the Northern Nevada Bar Center. This class fulfills 1 CLE Ethics Hour and registration can be made online at this website.

Ben T. Railsback, M.S., P.E. presents “Low Speed Impact” at the Colorado Claims Association Annual Seminar on October 7, 2011, at the Inverness Hotel in Englewood, CO. More information can be found at the Colorado Claims website.

Paul Bennett, P.E., CBIE speaks at the All Industry Day sponsored by the Colorado Chapter of the Chartered Property Casualty Underwriters (CPCU) Society on November 1, 2011. The title of his presentation is “Construction Law and the Ethical Expert Witness“. More information is available at the CPCU Society website.

Knott Laboratory now has a YouTube channel where you can see our latest animations.