Rick F Guyon - Differential Equations - Convolution Integral - Richard F Guyon

Rick F Guyon - A complex Laplace transform, F(s), will often be recognized as the product of two other transforms, F1(s) and F2(s), whose corresponding functions fi(f) and f2(t) are known. Unfortunately, Laplace transforms cannot be computed with ordinary multiplication. However, it is possible to extract f(t) from the convolution, as calculated from either of the convolution integrals.

Rick F Guyon - Convolution Integral - Richard F Guyon 

Rick F Guyon - Analysis of Accident Data - Richard F Guyon

Rick F Guyon - Accident data are compiled and evaluated to identify hazardous features and locations, set priorities for safety improvements, support economic analysis, and identify patterns, causes and possible countermeasures.

Accidents are classified into three severity categories,  depending on whether there is (a) property damage only referred to as PDO accidents, (b) personal injury, or (c) fatalities. The severity ratio is defined as the ratio of the number of injury and fatal accidents divided by the total number of all accidents (including PDO accidents).

It is common to prioritize intersections according to the accident rate, R. The accident rate may be determined for PDO, personal injury, and fatal accidents or the total thereof. The accident ratio is the ration of the number of accidents per year to the average daily traffic, ADT. The rate is reported as RMEV.

Rick F Guyon - Vehicle Exposure - Richard F Guyon

Routes between points are prioritized according to the accident rate per miles, calculated as the ratio of the number of accidents per year to the ADT per mile of length, counting traffic from all directions in the intersection. For convinces, the rate may be calculated per 100 million vehicle miles.

Rick F Guyon - Speed Degredation on Uphill Grades - Richard F Guyon

Rick F Guyon - Most modern passenger cars traveling on highways are capable of negotiation uphill grades of 4 to 5% without speed decreases blow their initial level-highway sppeds. (Older cars with high mass-to-power ratios and some smaller-sized "economy" vehicles may experience speed decreases.)

Heavy trucks experience greater speed degradation than passenger cars. The primary variables affecting actual speed decreases are the grade steepness, the grade length,  and the truck's mass-to-power ration. Mass to power ratios are commonly stated in pounds per horsepower and kilograms per kilowatt.

Rick F Guyon - Braking and Deceleration Rate - Richard F Guyon

Rick F Guyon - Continuing on this series on Vehicle Dynamics is Braking and Deceleration Rate.

The maximum deceleration that can be developed in dry weather by a vehicle with tires and brakes in good condition is about 25 ft/sec. (Acceleration and deceleration are sometimes specified in miles per hour per second, or kilometers per hour per second. Multiply mphps by 1.467 to obtain ft/sec and multiply kphps by 0.278 to obtain m/s2. However decelerations of 14 ft/sec are experienced by occupants as uncomfortable and alarming. 11 ft/sec is the appropriate upper limit of desirable decelerations,  and approximately 9ft/sec is the maximum comfortable deceleration from high-speed travel.