“The influence of paid parking on congestion in an urban environment”
By: R.H. van den Berg
Stn. 350081
Erasmus University Rotterdam, 2014
For most people, the car is considered a piece of freedom, the car provides you with a way to go wherever you want whenever you want. This belief is what makes people addicted to their cars, even in situations where driving is beyond rational, people keep on driving their cars. In large urban areas, driving a car can be a hassle due to heavy congestion and parking problems. Both congestion and parking problems are harmful to society, as they produce a loss in time and money, also they add to pollution and environmental problems. The problem of congestion tends to get worse, as the amount of traffic still increases, the peaks get higher and last longer, and travel predictability decreases. To stop this trend research has to be conducted in order to find out what causes it, and how the increase of congestion can be put to a halt. One possible solution to reduce the amount of congestion is by a system of paid parking. It is believed that the payment for a parking spot influences the amount of congestion. By providing an overview of existing literature, the aim is to determine the influence, paid parking has on congestion. The focus lies upon an urban environment.
1.Introduction
2. Congestion
2.1 Defining congestion
2.2 The problem of congestion
2.3 Types of congestion
2.4 Causes
2.5 Solutions
3. Parking
3.1 Why is parking often paid?
3.2 Basic economics
3.3 Parking facilities
On-street parking
Off-street parking
Public vs. Private
3.4 Governmental and local municipal intervention
Tools of the government
4. The influence of paid parking on congestion
4.1 Fewer cars in the city
4.2 Cruising for parking
Modelling cruising
The cause and effect of cruising
4.3 Double dividend effect
5. Conclusion and discussion
Bibliography
1.Introduction
For most people, the car is considered a piece of freedom, the car provides you with a way to go wherever you want whenever you want. This belief is what makes people addicted to their cars, even in situations where driving is beyond rational, people keep on driving their cars. In large urban areas, driving a car can be a hassle due to heavy congestion and parking problems. Both congestion and parking problems are harmful to society, as they produce a loss in time and money, also they add to pollution and environmental problems. The problem of congestion tends to get worse, as the amount of traffic still increases, the peaks get higher and last longer, and travel predictability decreases (OECD, 2007). To stop this trend research has to be conducted in order to find out what causes it, and how the increase of congestion can be put to a halt. One possible solution to reduce the amount of congestion is by a system of “paid Parking”. It is believed that the payment for a parking spot can influence the amount of congestion. By providing an overview of existing literature, the aim is to determine the influence paid parking has on congestion.The focus lies upon an urban environment. This leads to the research question: “What is the influence of paid parking on congestion in an urban environment?”.
Literature suggests that there are two main factors by which parking should have an effect on congestion. The first works thru the simple theory of supply and demand. An increase in the parking price should decrease the demand for parking, resulting in less traffic in the central city. However an increase in parking tariffs has some distorting effects which makes the theory of supply and demand a bit more complicated. Research by Glazer and Niskanen(1992, p.123) and by Roth and Thomson (1963, p.185) already indicated that a tax on parking can have unwanted effects in the behaviour of parking traffic and other kinds of traffic. So as it appears the influence of an increase in parking tariffs is not as straightforward as you might think. The second factor by which parking influences congestion is cruising for parking. The idea behind this is that when the price of parking increases, the demand for parking decreases. This will lead to a lower occupancy rate of the parking facilities, which allows parkers to freely park their car, without having to drive around, and “cruise” for parking. Cruising for parking constipates the roads, leading to a lot of urban congestion. In parking it is assumed that the price is the determent of whether one cruises or not, but research by Shoup(2006, p.479) and by Ommerenet al.(2012, p.123) suggest that there are more factor determining whether one cruises. This might influence the effect a price increase has on congestion. Research by Kelly and Clinch (2006, p.487) conclude that the purpose of the trip has an effect on the occupancy levels of the parking facilities. This makes you question whether the price is the real tool to intervene in the parking market in order to reduce cruising. So also the influence of paid parking on congestion thru cruising is worth some more examining.
In order to determine the influence of paid parking on congestion, it is important to understand both terms. In the first section, congestion is handled in order to get a broader view of the concept. Next we discuss the economics and specifics of parking. The idea behind the second to last part is to really zoom in on the effects of paid parking on congestion. The two main effects, the effect of cruising and the effect of a decrease in the amount of parkers are investigated, and also some side effects parking has on congestion are looked upon. Evaluating the effects of these factors will results in the final part about the conclusions and remarks.
2. Congestion
2.1 Defining congestion
In determining the influence of paid parking on congestion the first step is to define congestion. Most drivers of automobiles will probably define congestion as a situation in which they are slowed down by the other traffic, or a situation in which one gets “stuck in traffic” Some will consider traffic being congested, the moment there is a reduction in speed caused by the other vehicles, and others considers the road congested the moment the traffic comes to a near complete halt. The reason that congestion hasn’t got a single definition can be explained because it can be seen as a phenomenon consisting of a physical and a relative component (OECD, 2007). Congestion is a physical phenomenon in the way that vehicles have an impact on each other’s speed and progression when the roads get more occupied. The relative phenomenon relates to the expectation the drivers have on traffic congestion in comparison to the actual traffic circumstances. While the physical component can often be measured, by for instance induction-loops in the road, the relative component remains subjective.
Defining congestion can also be done in a purely theoretical way. The use of roads can be seen as a private good as it is both rivalry and excludable (Mallard & Glaister, 2008). Where one car drives the other can’t drive, or he is affected by the others driving. And cars can be banned from the streets or certain roads by legislation, which makes it excludable. As in all traded goods there is supply and demand, and when there is no equilibrium, inefficient outcomes may occur. Congestion may simply be seen as the consequence of the demand for road usage exceeding the supply of it. With this description, solving the congestion problem would seem to be just a matter of increasing supply or decreasing demand. Indeed often the solution can be found in simple economics but the problem with this theoretical approach is that both the supply and demand can’t be seen as fixed variables. The “supply of road” doesn’t only change by road construction but also by the speed of vehicles, accidents, and even the weather. Demand also varies a great deal every day, week, month and season, depending on time of the day, and again the weather. So there might be sufficient supply but the roads can still be congested, for instance by traffic accidence.
The best alternative to this modelled and oversimplified definition comes from the European Conference of Ministers of Transport(ECMT). In 1999 they came up with a more practical and elaborate definition.
“Congestion is the impedance vehicles impose on each other, due to the speed-flow
relationship, in conditions where the use of a transport system approaches its capacity.”
First of all, this definition describes the effect one vehicle and especially a new vehicle entering the road has on vehicles already making use of the road. This effect consist of the space the vehicle uses and the impact it has on the space of other vehicles. These two factor may cause congestion, but aren’t inherently the cause of congestion. The definition also comprehends with the speed-flow relationship, in which the traffic can have different effects on the flow and speed of the traffic, when the roads get near saturation the traffic can either keep flowing or come to a halt.
This definition might be complex but it comes best to gasp the full meaning of “congestion”.
2.2 The problem of congestion
Countless research has been conducted, figuring out what kind of congestion exist, what causes it, and mostly how it can be solved. Congestion appears to be a large social problem that needs to be solved. But why is congestion a problem, and to whom? In the textbook of Mallard and Glaister (2008) congestion is conceived as a problem because of four reasons. Congestion produces a loss in time, a loss in energy, it produces pollution, and it can be hold accounted for an increase in accidents. In comparison to a situation where one can freely drive to their destination, congestion cost time. If you end up in congestion, you are longer on your way to a destination. A loss in time is harmful because time has value and getting stuck in traffic thus means a financial loss. When you lose time at a moment you can’t afford to do so, a loss occurs that sometimes can’t be expressed in monetary terms. During the congestion you also burn more fuel than you would if you could just keep on driving. This is an example of the loss in energy that occurs when stuck in traffic. In congested situations you constantly have to apply the brake, and accelerate again.This, in combination with the fact that your engine is running for a longer amount of time, makes congestion a big polluter (Donohue, 1990). Congestion also has an effect on the number of accidents. In a study conducted in California, it was discovered that in a congested situation the chance of an accident is 1.5 times higher per vehicle-mile (Vickrey, 1969).
Nowconcerning the question, to whom is congestion a problem, the answer is to all of us. Not only the people driving the vehicles are effected by traffic jams, but congestion also reduces the total welfare. Also citizens not driving are affected by the exhaust fumes, and the increased risk in accidents. Plus when congestion has an effect on the total welfare thru the economy, everyone is affected.
2.3 Types of congestion
Next to defining congestion it is also important to distinguish the different kinds of congestion as every kind can have a different cause and different consequences. When looking at the effect of paid parking on congestion, it is important to know what kind of congestion it is and if it can be traced back to the parking facilities. There is no limit on the number of congestion types but at least six types can be distinguished in order to describe the kind of congestion, and how the traffic is moving. The six main kinds of congestion are single interaction, multiple interaction, bottleneck situations, trigger neck situations, network and control and general density (Vickrey, 1969). These forms can occurs independently from each other, but in practise they often coexist.
Single interaction is a situation in which two vehicles have an impact on each other’s speed. For instance when two vehicles approach an intersection one has to wait for the other, or slow down in order to avoid a collision. In this case besides the crossing car, the whole street or even town can be empty but that one vehicle still has an impact on the progression and speed of the other vehicle. This can be viewed of as a chief form of congestion.
The multiple interaction situation is a bit more enhanced. These situations occur at higher levels of traffic density. In comparison with the previous example concerning the single interaction situation, there are now multiple vehicles involved at the intersect. First the vehicle who has to stop in order to give another vehicle the right of way, is as in the single interaction situation affected in his progress. But in this situation there are also cars not involved in the initial situation, who are indirectly affected by it. For instance because they need to slow down because the car in front of them is still picking up speed, and this in turn has an effect on the person behind him, and the person behind him might see brake lights so also decides to step on the brake, and so forth. In the multiple interaction situation the initial cause has a longer lasting effect on traffic not involved in the initial confrontation.
A bottleneck situation is created by a segment of the road which capacity is smaller relative to traffic demand than the preceding or succeeding part of the road. This doesn’t have to be a problem as long as the traffic flow is below that of the capacity of the bottleneck. Even in this situation though, there might be congestion at the bottleneck as a consequence of heavy stochastic variations in the traffic flow, but on average these should disappear quickly. The real problem occurs when the traffic continuously exceeds the capacity of the bottleneck, in this case the queues will keep on accumulating until a solution is found.
A triggerneck situation is one of the consequences of the bottleneck. The bottleneck will produce queues occupying the road, blocking intersections and road exits. This makes other road users unable to freely get to their destination. So vehicles not even intending to use the bottleneck may also get stuck in traffic, and in their term cause another queue which causes another queue. A circular chain of trigger necks can cause a total standstill in urban environments, and even on highways.
In situations where peak-traffic may cause heavy congestion, the traffic is often regulated by stop signs, traffic lights, routing limitations and other control measurements. These measurements are used to control and ease the congestion and are often successful in diminishing it. These measurements can however, lead to congestion themselves in which case we speak of Network and Control congestion.
The last kind of congestion is general congestion which is created by the sum of the overall density of the transportation flows in the area.
2.4 Causes
Congestion can be caused by a tremendous amount of reasons. Most common are accidents, road works or weather conditions. All these have again underlying reasons linked to a more general condition like traffic safety, technology, and climate conditions. This makes the determining of the real cause of congestion hard. There is often a combination of a direct lead for the congestion and a more general cause like high traffic density.
This is why reasons for congestion can best be divided into three causal factors (OECD, 2007). Micro-level factors, macro-level factors, and exogenous factors. Micro-economic causes relate to the “triggers” of congestion on the road, these are the direct causes that can be found on the road like an accident or a bottle-neck situation. The macro-level relates to the “drivers” of congestion, these are the factors driving the demand for road use and thereby influencing congestion in a more general way as they aren’t directly linked to the congested situations. Examples of these are increasing population, land use, economic growth, or parking. The exogenous factors relates to patterns and the volume of traffic flow.
Figure 2.1 A schematic view of the different causes of congestion at micro and macro level.
Source: Original from Bovy and Hoogendoorn (2000), adapted by the OECD (2007)
Figure 2.1 displays how the micro-triggers, macro-drivers and exogenous factors independently and jointly influence congestion.
Besides trying to discover the causes of congestion by separating them into triggers or drivers, congestion can also be divided into recurrent and non-recurrent. This division is of importance because both have different solutions if you want to solve the congestion on a particular road segment.
Recurrent congestion refers to the fact that the factors causing the congestion occur periodically, for instance commuting to work, or weekend family visits. These recurrent congestions can be predicted with reasonable accuracy because they happen often and have the same causes every day or week. This is in contrast to the non-recurrent congestion, which can’t be predicted because they haven’t got a fixed pattern throughout the month. They happen unexpected and can be caused by a great variety of reasons like a accidents, a special event, or an unexpected summer day, causing everyone to go out and enjoy the weather. These non-recurrent congestions are hard to solve because when they occur the cause is often different, and so is the solution. This makes it interesting to try to predict these unexpected causes of congestion. In the case of accidents, regression analysis on particular road segments or intersects can predict the chance of an accident happening on set road or intersect. By means of statistical analyses one can even check the influence factors like the weather or school holidays have on the chance of an accident that evening. Knowing which roads or intersects are more prone to crashes has great advances in preventing or quickly clearing the congestion. The same counts for predicting the effects of hot-days or special events. With these regressions and predictions a lot of non-recurrent congestion can be prevented by active congestion management. The estimated non-recurrent congestion percentage for European counties is 55 percent while in urban-regions management policies have often reduced this to 14 to 25 percent of total congestion (OECD, 2007).