MODULE 5: Traffic Flow

Question 1

Is the study of interactions between travelers (humans and vehicles) and infrastructures.

Answer 1

Traffic Flow

Question 2

It is the arithmetic mean of speed of all vehicles passing a point during a specified interval of time.

Answer 2

Time Mean Speed (𝜇𝑡)

Question 3

Formula for Time Mean Speed

Answer 3

𝜇𝑡 = ∑𝜇𝑖 / 𝑛

Question 4

Is the harmonic mean of speed of vehicles occupying a relatively long section of street or highway at a given instant.

Answer 4

Space Mean Speed (𝜇𝑠)

Question 5

Formula for Space Mean Speed if the distance is same or constant but different times

Answer 5

𝜇𝑠 = 𝑛𝑑 / ∑𝑡𝑖

Question 6

Formula for Space Mean Speed for different distances but same time

Answer 6

𝜇𝑠 = ∑𝑑 / 𝑛𝑡𝑖

Question 7

Formula for variance

Answer 7

𝜇𝑡 = 𝜇𝑠 + (𝜎² / 𝜇𝑠)

Question 8

Formula for Standard Deviation

Answer 8

𝜎 = √variance

Question 9

The time mean speed will always be _____ than space mean speed

Answer 9

greater

Question 10

The number of vehicles per unit time passing a point in space and is usually expressed in vehicles per hour

Answer 10

Flow (q)

Question 11

The number of vehicles counted in a specified time interval

Answer 11

Volume (q)

Question 12

Ratio of the total hourly volume to the maximum rate of flow within the hour

Answer 12

Peak Hour Factor (PHF)

Question 13

Formula for Peak Hour Factor

Answer 13

PHF = Hourly Volume / (60/15)*(Highest Volume)

Question 14

The number of vehicles per unit distance occupying a section of a roadway at a given instant time and is usually measured in vehicles per mile or per kilometer.

Answer 14

Density

Question 15

Formula for Density

Answer 15

K = n/d

Question 16

The ratio of the sum of the lengths of the vehicles to the length of the road section in which those vehicles are present.

Answer 16

Occupancy

Question 17

Formula of Occupancy

Answer 17

O = ∑L / 𝑑

Question 18

Rate of change of distance with respect to time

Answer 18

Speed

Question 19

The reciprocal of speed

Answer 19

Rate of travel

Question 20

The time elapsed between common points on successive vehicle

Answer 20

Headway (H)

Question 21

The time elapsed between the rear of one vehicle to the front of the next vehicle

Answer 21

Gap (g)

Question 22

The distance between common points on successive vehicle

Answer 22

Space (S)

Question 23

The distance between the rear of one vehicle to the front of the next vehicle

Answer 23

Clearance (c)

Question 24

Formula for headway

Answer 24

H = 1/q

Question 25

Formula for gap

Answer 25

G = H - Vehicle Length (in time)

Question 26

Formula for Space

Answer 26

S = 1/k

Question 27

Formula for clearance

Answer 27

S - Vehicle Length (in distance)

Question 28

The average speed that a motorist would travel if there were no congestion

Answer 28

Free Flow Speed

Question 29

The maximum density under free flow

Answer 29

Critical density (kc or Do)

Question 30

The maximum density under congestion

Answer 30

Jam Density (kj or Dj)

Question 31

The maximum number of vehicles that can pass a given point on a lane or roadway for one hour

Answer 31

Maximum Capacity (qcap)

Question 32

Formula for Jam Density

Answer 32

Kj = 4qcap / 𝜇f

Question 33

Another formula to solve for density

Answer 33

q = K𝜇f - (𝜇f/Kj) (K²)