Chapter objectives:

-                 understanding the importance of traffic modeling in relevant software,

-                 understanding the theory of traffic flow,

-               knowledge of monitored traffic flow parameters.

Time required to study the chapter: 6 hours

Interpretation:

 

Modeling individual passenger transport can be divided into three phases:

1.phase

In the first phase, a simulated communication network is created. The network consists of nodes and sections. Nodes represent intersections, sources and destinations of transport, and places where communication characteristics changes. Sections represent communications which interconnect the road network nodes.

2.phase

In the second phase, the particular territory is divided into areas (regions) in which transport originates and ends. For such divided regions, transport relations matrices are defined, on the basis of transport surveys, which determine how much traffic is in motion among transport areas and entries to the territory.

3.phase

In the third phase, journeys according to the transport relations matrix are assigned to the current communication network. For each relationship, one or more routes are searched according to the defined parameters.

 

Model possibilities (functions)

o  Determining traffic intensities on newly constructed roads and specifying the decrease or increase in traffic on the existing road network;

o  Construction phasing assessment;

o  Road sections closure simulation;

o  Impact of the traffic organization assessment - construction of unidirectional roads and road sections closures, forbidden turning of some directions at intersections, "Green wave";

o  Determining transit, destination and initial transport to the given territory;

o  Determining overall traffic and transport characteristics - total transport performance, average journey time, total time consumption, etc.

 

Basic terms:

Road lane - the basic part of the road section intended for one traffic flow of road vehicles or the main traffic lane of a one-way road.

Traffic lane - a reinforced part of the road section intended for one traffic flow of road vehicles or pedestrians.

Traffic flow - a sequence of all vehicles (or pedestrians) moving in the lane either in succession or in lanes side by side in one direction. It can consist of several road or pedestrian flows.

Traffic flow intensity - the number of road vehicles or pedestrians who pass through a certain road profile or its part over a selected time period in one traffic direction.

Rush (peak) hour intensity - maximum intensity of vehicles, pedestrians or cyclists which pass through an observed road profile per hour.

Traffic flow structure - it expresses the share of individual vehicle types from their total sum at a certain time period and observed road section.

Traffic flow density - the number of vehicles (pedestrians) on a particular road section at a certain time period.

Traffic flow speed - mean value of vehicles (pedestrians) speed in a selected road profile (instantaneous speed).

Unit vehicle - a theoretical vehicle indicating the conversion of all vehicles to its value. It is expressed by the characteristic features (driving mainly) of a passenger car.

 

Study materials:

Basic literature:

JIRAVA, P., SLABÝ, P. Dopravní inženýrství. Prague: Ediční středisko ČVUT, 1990, 165 p., ISBN 80-01-00213-6

Voženílek, V., Strakoš, V. City Logistics: Dopravní problémy města a logistika. Olomouc: Publisher – Palacky University, 2009, pp. 63-74. ISBN 978-80-244-2317-3

Recommended study literature:

TANIGUCHI, E. et al. Urban Transportation and Logistics: Health, Safety, and Security Concerns. 1st.: CRC Press, 2013. 280 p. ISBN 978-1-4822-0909-9.

 

Questions and tasks

1.        Modeling individual passenger transport can be divided into:

a)      3 phases

b)      10 phases

c)      15 phases

2.        “Road lane” is defined as:

a)      the basic part of the road section intended for one traffic flow of road vehicles or the main traffic lane of a one-way road

b)      a sequence of all vehicles (or pedestrians) moving in the lane either in succession or in lanes side by side in one direction.

c)      a reinforced part of the road section intended for one traffic flow of road vehicles or pedestrians

3.        Define the term: “traffic flow structure”

4.        Traffic flow density is:

a)      the share of individual vehicle types from their total sum at a certain time period and observed road section

b)      the number of vehicles (pedestrians) on a particular road section at a certain time period

c)      a sequence of all vehicles (or pedestrians) moving in the lane either in succession or in lanes side by side in one direction.

 

Key to solve the questions:

1)    a.

2)    a.

3)  The share of individual vehicle types from their total sum at a certain time period and observed road section

      4)  b.