## Speed Conversion

**Helpful for Vascar to check if the speed you are charged with is correct**

**Conversion: Time Distance Speed Miles Per Hour To Feet Per Second**

Miles per hour can be changed to feet per second by multiplying the number of miles per hour by the feet in a mile (5,280) and dividing by the seconds in an hour (3,600). This is approximately equivalent to multiplying miles per hour by 1.47 (which is 5,280 / 3,600 to two decimal places).**Mathematical Formula**

v = 1.47s

v = velocity (feet per second)

s - speed (miles per hour)**Example**

60mph = 5,280 / 3,600 = 88 ft per sec exactly or

60mph = 60 x 1.47 = 88.2 feet per second approximately

Rough estimates: miles per hour can be multiplied by 1.5

Put another way, half the number is added to the number

**Example**

60mph = 60 x 1.5 = 90 ft per see, approximately or

60 mph plus 30 mph (half that amount) = 90 ft per sec, approximately

**Conversion: Time Distance Speed Miles Per Hour To Feet Per Second**

Miles per hour can be changed to feet per second by multiplying the number of miles per hour by the feet in a mile (5,280) and dividing by the seconds in an hour (3,600). This is approximately equivalent to multiplying miles per hour by 1.47 (which is 5,280 / 3,600 to two decimal places).**Mathematical Formula**

v = 1.47s

v = velocity (feet per second)

s - speed (miles per hour)**Example**

60mph = 5,280 / 3,600 = 88 ft per sec exactly or

60mph = 60 x 1.47 = 88.2 feet per second approximately

Rough estimates: miles per hour can be multiplied by 1.5

Put another way, half the number is added to the number

**Example**

60mph = 60 x 1.5 = 90 ft per see, approximately or

60 mph plus 30 mph (half that amount) = 90 ft per sec, approximately

**Conversion: Velocity to Speed Feet Per Second To Miles Per Hour**

Feet per second can be changed to miles per hour by multiplying by the seconds in an hour (3,600) and dividing by the feet in a mile (5,280). This is approximately equivalent to dividing by 1.47 or multiplying by 0.682 (3,600 / 5,280 to three decimal places)**Mathematical Formula**

s = v / 1.47 or s = 0.682v

v = velocity (feet per second)

s - speed (miles per hour)**Example**

66 ft per sec = 66 x 3,600 / 5,280 = 45 mph exactly or

66 feet per second = 66 x 0.682 = 45.0 mph approximately

Rough estimates: miles per hour is two thirds of feet per second**Example**

two thirds of 66 feet per second is 44 miles per hour approximately or

66 feet per second = 66 x 2 = 132 / 3 = 44.0 mph approximately

66 feet per second = 66 x 0.682 = 45.0 mph approximately

Multiplying by 2/3 (0.6667) is roughly the same as dividing by 1.5**Example**

66 feet per second = 66 / 1.5 44.0 mph approximately

**Conversion: Velocity to Speed Feet Per Second To Miles Per Hour**

Feet per second can be changed to miles per hour by multiplying by the seconds in an hour (3,600) and dividing by the feet in a mile (5,280). This is approximately equivalent to dividing by 1.47 or multiplying by 0.682 (3,600 / 5,280 to three decimal places)**Mathematical Formula**

s = v / 1.47 or s = 0.682v

v = velocity (feet per second)

s - speed (miles per hour)**Example**

66 ft per sec = 66 x 3,600 / 5,280 = 45 mph exactly or

66 feet per second = 66 x 0.682 = 45.0 mph approximately

Rough estimates: miles per hour is two thirds of feet per second**Example**

two thirds of 66 feet per second is 44 miles per hour approximately or

66 feet per second = 66 x 2 = 132 / 3 = 44.0 mph approximately

66 feet per second = 66 x 0.682 = 45.0 mph approximately

Multiplying by 2/3 (0.6667) is roughly the same as dividing by 1.5**Example**

66 feet per second = 66 / 1.5 44.0 mph approximately

**VISUAL ESTIMATE**

As a part of radar or vascar training in most States, officers must make visual estimates of speed. To become certified and receive a wallet certification card, each must accurately estimate speeds: *(since this changes on occasion you should check with you highway department or in the State Statutes to see what your State requires)*

On the sit" 10 estimates plus or minus 3 miles per hour

On the move" 5 estimates plus or minus 5 miles per hour

To quote the TV credit card commercial: "What's in your wallet?"

Hopefully, the officer doesn't possess the certification card. If he doesn't, ask for dismissal.