1.19 Describe the factors affecting vehicle stopping distance including speed, mass, road condition and reaction time

Stopping distance = Breaking + Thinking distance

Things that could affect this include:

• Mass of the vehicle ~ The more mass, the more momentum, meaning it is harder to stop.
• Speed (velocity) of vehicle ~ The faster, the harder to stop
• The state of the driver 
• Weather conditions ~ Snow, ice and rain can make the road slippery
• Condition of the tyres ~ If more worn, less grip so it will slip more easily
• Condition of the brakes ~ If more worn, they have less of a grip on the inner wheel bit thingie (what's it called?) 

Condition of driver

Drugs, tiredness, alcohol etc. increase thinking distance while things such as caffeine can temporarily increase alertness.