CHAPTER ONE
INTRODUCTION
Road traffic is referred to as all forms of vehicles and transport modes applying on roads. These include cars, buses, bicycles, motorcycles and trucks etc.
Hence traffic delay involves all activities resulting in slowing up, hindrance or lateness in vesicular traffic movement. Hence delays studies of traffic on a given network route so as to determine the level of service of the route involved.
Since mobility is part of our society, each day millions of people travel to and from work, shops, sports. Goods are transported between locations to end – up in stares or end – user. When too many people or goods want to use the same infrastructures all the same time, a boatel develops After all each infrastructure has a maximum capacity. And in traffic, this bottlenecks results in congestion and hence delay result.
1.1 Background of Study
It has been observed that, the numbers of journeys in urban areas grow year on year, traffic in towns and cities get worse. This problems is increased by the fact that systems do not always work as effectively as they could do,
Uyo has not been left out in the increase in vehicular traffic. The ancient city has been recently witnessed a steady increase in the numbers of vehicular traffic playing major routes Abak road inclusive. With a handful of these vehicles and the attendant insufficiency and poor functionality of control measures, traffic congestion and delay result.
These researches seek to investigate and study the delays in section of Abak road and IBB round – about, hence estimating the level of service in this route.
1.2 Problem Statement
As far as Uyo is concerned, and Abak road to be specific there have been problem of serious delays on daily basis, due to the intersection of various factors such as congestion, inadequacy of carriage way widths, mixed traffic conditions, parked cars and heavy pedestrian flow, non functionality of traffic signals, faded road markings. This conflict will be observed mostly in morning and evening peak hours when people are going and returning from work.
1.3 Aim
The aim of this research is to cheek the level of service and efficiency of the assigned routes by studying their delays and hence providing measures of minimizing conflicts.
1.4 Objectives / Reasons for Engaging in this Research
- This research will be carried out to assess user in travel time caused by congested conditions.
- To determine the level of service and delay on these routes
- To suggest measure of improving traffic circulation on our road for the motoring public.
- To assess the effectiveness of improvement measures
- For determination of traffic control measures and signal suitable for these routes.
- To assist the public in best selection of model devices while working towards the routes.
1.5 Scope of the Research
For the purpose of this study, the scope is limited to Abak road taking IBB roundabout, Ukana – Offot junction and Udo – Eduok junction, involving delay studies and journey time assessment to determine the level of service (LOS), magnitude of congestion, loses in travel time and hence the effectiveness of control measures on these routes.
It will involves Manvel collection and collation of raw data on field for a period not less than an hour, for both morning and evening peak periods and an off- peak period for a specified period of time.
1.6 Definition of Terms
Journey speed: Also known as overall travel speed is the effective speed of a vehicle between the points. And divided by the total travel time taken by vehicles to complete the journey including all delays incurred en-route mathematically
Journey speed = Distance
Total Journey time (including delays)
Delay: This is seen as the sum total of the difference in actual time spent in transit and estimated travel time due to driver’s interaction with other road users in the course of the Journey. Here the vehicle is slowed down or hindered.
Travel Time: the time taken for a traveler to move from one point on a road to another.
Running speeds: is the average speed maintained by a vehicle over a given course while the vehicle is in motion excluding delays mathematically,
Running speed = Length of course
Running time – Delay
Peak Hour: This is the time where high volume of traffic is noticed on some parts of the network which are business routes. Either while people are heading to or from work it could either be in the morning or evening this time ranges from work 7am – 10am in the morning and could be from 5pm – 9pm in the evening.
Peak Days: These are days in which high volume of traffic is observed on network routes.
HIGHWAY CAPACITY
The capacity of a facility is the maximum number of persons or vehicles per hours; that can be reasonably expected to traverse a point or a uniform section of a lane or roadway during a given time period under the prevailing roadway, traffic and control conditions.
Vehicle capacity is the maximum number of vehicles that can pass a given point during a specified period under prevailing roadway, traffic and control conditions. This assumes that there is no influence from downstream traffic operation such as the backing up of traffic into the analysis point.
Person capacity is the maximum number of persons that can pass a given point during a specific period under prevailing condition. Person capacity is commonly used to evaluate public transit services, high – occupancy vehicle lanes and pedestrian facilities.
Prevailing roadway, traffic and control conditions define capacity.
Reasonable expectancy is the basis for defining capacity. This is, the stated capacity for a given facility is a flow rate that can be achieved repeatedly for peak periods of sufficient demand.
DEMAND
Demand is the principal measure of the amount of traffic using a given facility demand relates to vehicles arriving; volume relates to vehicle discharging. If there is no queue, demand is equivalent to the traffic volume at a given point on the roadway.
QUALITY AND LEVELS OF SERVICE
Quality of service requires quantitative measure to characteristics operational condition within a traffic stream. Level of service (LOS) is a quality measure describing operational conditions within a traffic stream, generally in terms of such service measures as speed and travel time, freedom to maneuver, traffic interruption comfort and convenience.
FACTORS AFFECTING CAPACITY AND LOS
BASE CONDITIONS
Base conditions assume good condition, good pavement condition, and user familiar with the facility and no Impediments to traffic flow.
- Base conditions for uninterrupted flow facilities are:
– Lane width of 3.6m
– Clearance of 1.8m between the edge of the travel lane and the nearest obstruction or objects at the roadside and in the roadside and in the median.
– Free-flow speed of 100km/h for multi lane highways
– Only passenger cars in the traffic stream (no heavy vehicles)
– Level terrain
– No no-passing zones of two-lane highways and
– No impediments to through traffic due to traffic control or turning vehicles.
- Base conditions for intersection approaches are:
– Lane widths of 3.6m
– Level grade
– No kerb parking on the approaches
– Only passenger cars in the traffic stream
– No local transit buses stopping in the travel lanes
– Intersection located in a non-central business districts area
– No pedestrians.
In most capacity analyses, prevailing conditions differ from the base condition, and computation of capacity, service flow rate and level of service must include adjustments.
ROADWAY CONDITIONS
Roadway conditions include geometric and other elements. In some cases, these influence the capacity of a road; in others they can affect a performance measure such as speed but not the capacity or maximum flow rate of the facility.
Roadway factors includes:
- Number of Lanes
- The type of facility and its development environment
- Lane width
- Shoulder width and central clearance
- Design speed
- Horizontal and vertical alignments
- Availability of exclusive turn lanes at intersections.
The horizontal and vertical alignments of a highway depends on the design speed and the topography of the land on which it is constructed.
In general, the severity of the terrain reduces capacity and service flow rates. This is significant for two-lane rural highways; in here the severity of terrain not only affects the traffic stream, but can restrict opportunities for passing slow moving vehicles.
TRAFFIC CONDITIONS
Traffic conditions that influences capacity and service levels include vehicle type and lane or directional distribution.
VEHICLE TYPE
The entry of heavy vehicles into the traffic stream affects the number vehicles that can be served. Heavy vehicles adversely affect traffic in two ways:
- They are larger than passenger cars and occupy more roadway space.
- They have poorer operating capabilities than passenger cars particularly with respect to acceleration, deceleration and the ability to’ maintain speed on upgrades.
DIRECTIONAL AND LANES DISTRIBUTION
Directional distribution has a dramatic impact on two-lane rural highway operation, which achieves optimal conditions when the amount of traffic is about the same in each direction.
CONTROL CONDITIONS
For interrupted flow facilities, the control of the time for movement of specific traffic flows is critical to capacity service flow and level service. The most critical type of control is the traffic signal. The type of control in use, signal phasing, allocation of green time, cycle length and the relationship with adjacent control measures affect operation.
TECHNOLOGY
Emerging transportation technologies, also known as Intelligent Transportation System (ITS), will enhance safety and efficiency of vehicles and roadway systems.
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