Highway Safety And Accident Analysis

Question 1

Accident rates for 100 million vehicle miles of travel (HMVM) for a segment of a highway

Answer 1

R = A (100,000,000) / ADT × N × 365 × L

Question 2

Accident rates per million entering vehicles (MEV) for an intersection

Answer 2

R= A (1,000,000) / ADT × N x 365

Question 3

Severity ratio

Answer 3

Fatal + injury accidents / fatal + injury + property damage

Question 4

Space mean speed of a vehicle

Answer 4

Us = nd/ Sum ti

Question 5

Time mean speed of a vehicle

Answer 5

It = sum d/ti / n

Question 6

Rate of flow

Answer 6

q = K Us

Question 7

Spacing of vehicles

Answer 7

Number of vehicles per kilometer = volume of traffic in vehicles per hour / average speed of car in kilometer per hour

Question 8

Capacity of a single lane in vehicles per hour

Answer 8

C = 1000 ( V ) / S

Where S is

S = VT + L

Question 9

Minimum time headway

Answer 9

Ht = 3600 / C

Question 10

Time mean period

Answer 10

Ut= sum UI / n

Question 11

Space mean speed

Answer 11

Us = n / sum 1/U1

Question 12

Density of traffic

Answer 12

K = q / Us

K = R1 / average length of vehicles

Question 13

R1

Answer 13

R1 = some of vehicles lengths / length of roadway section

Question 14

Variance about the space means speed

Answer 14

Ut + Us = sigma s ² / Us

Question 15

5 minutes pick hour factor
PHF pick hour factor

Answer 15

PHF = some of flow rate in 1 hour / max peak flow rate × 60/5