Traffic Management and Control. Bayero University, Kano Nigeria

1. BY
IBRAHIM SAMBO AHMED
SPS/15/MCE/0025
LECTURER
Dr. M.H ALHASSAN
(Civil Engineering Department, BUK )

2. Road network literally refers to the framework of
routes within a system of location. According
to Rodrique et al (2006) transportation network
are of various types of links between points
along which movement can take place.
Samadzadegen et al (2004) noted that road
network is of prominent elements of urban
transportation life lines which directly affect
the urban city life. Rao and Jayasra (2010)
expressed that a proper skeleton of road
network creates a promotional impact of land
use activity in the urban centres.

3. Designing successful transportation networks
requires more than the application of the
functional classification. In order to assist
stakeholders in the design process, a step-by-step
design process is set up. It is not a blueprint that
tells stakeholders exactly what to do, merely a
framework within which they make decisions. The
stakeholders get to make the designs, but the
method brings structure to the design process, by
indicating which decisions need to be made at
what point in the process. It is based on a number
of important characteristics, which are listed in
random order in Figure below.

5. It is possible to describe the road network in different ways. The nine
statements presented below can all be used to describe the
performance of the road network in terms of accessibility.
1. A node has access to a network if a link exists between the node
and the network
2. The accessibility of a node with respect to a network is the distance
one has to travel to the nearest node on the next hierarchy network
3. The accessibility of a node in a network is the total number of direct
connections with other nodes
4. The accessibility of a node in a network is the total number of links
connected to this network
5. The accessibility of a node to another node is measured as the travel
cost between these nodes

6. 6. The accessibility of a node in a network is the weighted average travel cost
between particular node and all nodes in the network
7. The accessibility of a node in a network is the expected value of the maximum
utility of a visit to any node
8. The accessibility of a node in a network is (proportional to) the spatial
interaction between the node and all other nodes
9. The accessibility of a node in a network is the total number of people one can
reach from a node with in certain transport cost limit.
To describe the road network based on one or more of these phrases information
is needed about:
• The location of nodes (centres)
• The length of the links
• Data on transport costs, travel time, fares And sometimes information about
spatial patterns may be required, e.g. travel frequencies and traffic volumes.

7.  The hierarchy of roads categorizes roads
according their capacities. While sources differ
on the exact nomenclature, the basic hierarchy
comprises;
 Freeways
 Arterials
 Collectors and
 Local roads

8.  A road hierarchy has, for some time, been
accepted as one of the important tools used for
road network and land use planning. It is a
means of defining each roadway in terms of its
function such that appropriate objectives for
that roadway can be set and appropriate design
criteria can be implemented.

9.  These roads provide largely uninterrupted
travel, often using partial or full access control,
and are designed for high speeds. Some
freeways have collector/distributor lanes (also
known as local lanes) which further reduce the
number of access ramps that directly interface
with the freeway; rather, the freeway
periodically interfaces with these parallel
roadways, which allow the freeway to operate
with less friction at even higher speed and
higher flow.

10.  These are high-capacity urban roads. The
primary function is to deliver traffic from
collector roads to freeways or expressways,
and between urban centres at the highest level
of service possible.

11.  A collector road is a low-to-moderate-capacity
road which serves to move traffic from local
streets to arterial roads. They are also designed
to provide access to residential properties.
 Speed limits are typically 20-35 mph (or 30-55
km/h) on collector roads in built-up areas,
depending on the degree of development and
frequency of local access, intersections, and
pedestrians, as well as the surrounding area
(the speed tends to be lowest in a school zone).

12.  These roads have the lowest speed limit, and
carry low volumes traffic. In some areas these
roads may be unpaved. Local roads primarily
serve local traffic, provide connections within
communities, provide access to properties, and
usually have on-street parking.

13. The review shows that the state of Nigerian roads
remains poor for a number of reasons such as faulty
designs, lack of drainage and very thin coatings that were
easily washed away, excessive use of the road network
given the under-developed nature of waterways and
railways among others. The most important role of both
government and individual citizen is to find a solution for
managing existing roads even before new ones are
constructed but managing modern roadways is a complex
business especially at this time when economic growth
has come close to a halt in Nigeria.

14. Thus, the creation, updating, maintenance and general
management of road information and network in terms of spatial
and non-spatial data are needed but the voluminous nature of data
involved for proper record keeping is indeed cumbersome, and
cannot effectively be handled by a traditional system of record
keeping. The analogue system means remain inflexible resulting in
data storage in fixed forms and formats; however, the system
becomes less useful for many purposes and is rarely updated
because of the costs implication. The maps are easily displaced or
destroyed because many different people at different locations use
them.
An alternative approach to maintaining a coherent database for
roads in a scientific and efficient manner is therefore required and
consequently, geographic information systems (GIS) will be
advantageous. Hence, there will be improvements in planning,
implementation and operation of the road sector through
provision of timely, reliable, sufficiently and accurately detailed
data which will facilitate the decision making activities.

15. Most transport modes are experiencing rising
congestion and this directly affects the economies of
many nations. Relief for road congestion is an issue
all over the world.
Road Network Operations (RNO) concerns the
methods at the disposal of road authorities and
highway infrastructure operators that contributes to
safer and more efficient for road users and for society
as a whole. This include techniques such as traffic
incident detection, incident management, traffic
control (urban and inter-urban), traveller information
(pre-trip and on-trip), public transport priorities,
electronic payment and travel demand management
techniques.