Rahul Weekly Report January Last

WEEKLY REPORT Highway Linear Collision Prevention in Automobiles 29/01/2007 to 04/02/2007

Project Guide: Smt. Aparna Devi P S Project Coodinator: Smt. Sumitha Mathew

PROJECT GROUP MEMBERS: Rahul S Raj (ECU031/29) Deepu K R (ECU031/13) Sandeep Wilson (ECU031/34) Xavier George (ECU031/45) Anoop Kovoor (ECU031/05)

SPEED –MINIMUM STOPPING DISTANCE STUDY It is known that vehicles maintain distances between each other when travelling at speeds. It is noteworthy that the distance varies as the speed changes. A vehicle in a traffic (snail pace) can be stationed much closer to another than when travelling at high speeds in highways. Assuming proper operation of the brakes, the minimum stopping distance for an automobile is determined by the effective coefficient of friction between the tires and the road. The friction force of the road must do enough work on the car to reduce its kinetic energy to zero (workenergy principle). If the wheels of the car continue to turn while braking, then static friction is operating, while if the wheels are locked and sliding over the road surface, the braking force i s a kinetic friction force. To reduce the kinetic energy to zero: so the stopping distance is:

WorkFriction = -umgd = -.5mv2 d = v2/(2ug)

Note that this implies a stopping distance independent of vehicle mass. It also implies a quadrupling of stopping distance with a doubling of vehicle speed. For calculating minimum stopping distance, a value of 0.8 is a nominal value for the coefficient of static friction between good tires and a good road surface. Generally, coefficients of kinetic friction are less, and may be dramatically less for wet, icy, or oily surfaces. For many existing tires, the coefficient of kinetic friction on a dry road surface may approach 0.8 if the braking is not so prolonged as to cause tire melting. A table has been provided below with some sample values of sped to distance ratios. It has to be noted that the below table represents the minimum stopping distance, ie, it points out the maximum distance a vehicle can travel when brakes are applied at the given speed. In reality, distances can be anywhere less than or equal to these. Sample Table for Speed vs Minimum Distance Serial Number 1 2 3 4 5 6

Speed in metres per sec 1 3 5 10 15 20

Speed in kilometers per hour 3.6 10.8 18 36 54 72

Stopping Distance (metres) .0637 .5739 1.5943 6.3775 14.3949 25.5102

Graph of Speed (in Kms/hr) vs Minimum Stopping Distance (in metres)

Stopping Distance (metres) 30 25 20 15

Stopping Distance (metres)

10 5

0 0

20

40

60

80

So, based on this table, we will require to create a lookup table in our program so that the distance (proportional to these maximum values) is compared for specific speeds of the vehicle.