Road widening - Futility & Alternatives

BBMP listed 217 roads to be widened. This has caused much worry among citizens as it entails widespread destruction of both greenery & property. Why do so many roads need to be widened? What are the characteristics of congestion on this road? What are the traffic patterns on these roads? Should congestion be reduced by widening or by any other strategy? Are already widened roads being used efficiently? Have we addressed the efficiency of current road widths? This paper attempts to focus on the efficiency of current available road space and put widening into perspective as a long term strategy.

The simple truth is that building more highways and widening existing roads, almost always motivated by concern over traffic, does nothing to reduce traffic. In the long run, in fact, it increases traffic.

A recent University of California at Berkeley study covering thirty California counties between 1973 and 1990 found that, for every 10 percent increase in roadway capacity, traffic increased 9 percent within four years' time¹.

Yet another study, on why building wider roads isn’t the answer, in analyzing sixty road closures worldwide, found that 20 percent to 60 percent of driving trips disappeared rather than materializing elsewhere².

USA Today published the following report on Atlanta: "For years, Atlanta tried to ward off traffic problems by building more miles of highways per capita than any other urban area except Kansas City…As a result of the area's sprawl, Atlantans now drive an average of 35 miles a day, more than residents of any other city."· This phenomenon, which is now well known to those members of the transportation industry who wish to acknowledge it, has come to be called induced traffic.

The phenomenon of induced traffic works in reverse as well. When New York's West Side Highway collapsed in 1973, an NYDOT study showed that 93 percent of the car trips lost did not reappear elsewhere; people simply stopped driving.

This condition is best explained by what specialists call latent demand. Since the real constraint on driving is traffic, not cost, people are always ready to make more trips when the traffic goes away. The number of latent trips is huge--perhaps 30 percent of existing traffic. Because of latent demand, adding lanes is futile, since drivers are already poised to use them up.

Automobile use is the intelligent choice for most people because it is what economists refer to as a "free good": the consumer pays only a fraction of its true cost.  We learn in first-year economics what happens when products or services become "free" goods. The market functions chaotically; demand goes through the roof. In most cities, parking spaces, roads and freeways are free goods. Local government services to the motorist and to the trucking industry--traffic engineering, traffic control, traffic lights, police and fire protection, street repair and maintenance--are all free goods.³

A piece of statistic from the Mumbai Traffic Police web site illustrates the magnitude of the problem: While length of roads in Mumbai increased two times between 1951 and 2007, the population increased 5.4 times and the number of vehicles a whopping 43 times.

Another way of widening or adding lanes is to build elevated roads. Essentially it is another way to add bandwidth which is similarly destructive. In fact most countries are today opting to pull down the elevated highways they have built, following are some examples

What do we want?

The important question is not how many lanes must be built to ease congestion but how many lanes of congestion would we want? Do we favor four lanes of bumper-to-bumper traffic at rush hour, or sixteen? So what are we trying to do with these road widening projects? Are we looking to loosen the belt to accommodate the flab or do we have a plan in place to address the bulge?

There will pretty much always be a latent demand for more driving. Much of that demand is discouraged or diverted by congestion. Much of the discouragement goes away when the road is less congested.  

The key is not to strive to reduce congestion. A healthy city must provide alternatives to congestion: convenient bicycling/walking/transit, compact development, pricing roads/parking, etc. And all of these healthy alternatives are much more likely, politically, when there is a lot of congestion. It is no coincidence that those cities with the worst congestion have the best transit.⁴

Many cities have set modal share targets for balanced and sustainable transport modes, particularly 30% of non-motorized (cycling and walking) and 30% of public transport. A larger plan on limiting road facilities has to take into account provisions for public transport & NMT as well. The modal share of NMT is pretty abysmal for a populated country like ours. Today no road widening includes a default NMT/PT lanes. If transport involves moving humans from place A to place B in the most sustainable way we are exactly not doing that.

In the short term a lot of wastage in built out bandwidth is seen. This leads to traffic jams in addition to volume induced congestion. The effect of this suboptimal usage of bandwidth compounds the feeling of congestion and hence making us feel it is much worse than it actually is

Using existing road width efficiently

In India specifically, today there are many causes of misuse of the current bandwidth. The 3 E’s of traffic namely Engineering, Education & Enforcement are broken. This contributes to traffic jams which take the form of abrupt slowing down of traffic just to sort themselves out on the streets hence causing backups taking a while to unclog. Lets look at the following factors which slow down traffic

Bad Engineering

Inconsistent Lanes – Most lane markings on the roads are ill defined. The lane sizes vary anywhere from 3.5 to 4 meters or more in most stretches and are not consistent all along. Effects of this are merging, severe slowdown of movement and lower than average speed resulting from encroachment into each other’s lanes & fight over road space. This is undesirable as the road engineers have lost control of the traffic & have left the road users to define the space & fend for themselves.

The lane widths need to be  tighter at 3.3 meters & consistent all along.  Especially the outer lanes, toward the curb, tend to hold all excess road space as a part of the lane.  These extra space needs to be blocked for vehicular access by turning them into well marked space for parking or for pedestrians/NMT. The lanes are also discontinuous in most parts. All lanes need to have continuity and any break or merge needs to be properly marked with clear advanced instructions in the form of well-placed signboards

AdHoc Parking – Free parking as currently practiced in the city is a major contributor to this congestion in fact it has been observed in places like palace road that roads have been widened only to accommodate parking. If we have to make any impact in managing traffic we need to impose true cost of parking on the users. These free goods only compound the inducements already provided by widening.

Poor Quality roads – World Bank studies have confirmed that the economic losses due to insufficient  pavement  thickness  and  poor  riding quality is estimated to be of the  order  of  Rs. 30000 crores (300 billion) per annum. This is only the vehicular operation cost and does not include cost of traffic jams caused due to slowdowns & congestions It is clear that interruptions like potholes on the road slow down vehicles causes a backup & jams. Ensuring unscientific speed breakers & potholes are removed from the road

Insufficient traffic Channelizing – Traffic channelizing is the essence of traffic engineering. It is essential to tackle junctions & merges in such a way that there are no impediments to the speed of travel. The average speed of travel can be increased by keeping traffic flowing smoother at lower speed than by having a high speed corridor with many interruptions which bring down the average speed.  Junction optimization with synchronized signaling & vehicle actuated traffic lights can cut down on travel time significantly on key corridors

Bad driver Education

While Engineering lays down the standard for how the traffic should flow it is entirely useless of the drivers who use them are not aware of the appropriate driving practices. It has been found that drivers in the cities are from a lower socio economic background and arrive from places outside the city which do not have a high standard of road infrastructure. It is important then that these people are trained & certified/recertified on the upgraded infrastructure separately. A written & driving test in an RTO office should be made mandatory for people who have obtained license from outside the city. Transport department officials, Police & training institutes should have their staff certified by the Engineering team for proper usage of infrastructure. The transport department needs to also ensure basic vehicle conditions like tail lights & mirrors are in use and not broken or unusable.

Bad Enforcement

Enforcement in India is characterized by low fines leading to callousness by the vehicle user. Fines need to be increased to make  it a viable deterrent & respect needs to be inculcated for Pedestrians & Bicyclists. Transportation is heavily influenced by peer behavior as it is a social exercise. If people notice some people getting away with violations they are encouraged to do the same. Hence visible policing is important to set example and induce proper driving behavior.

Prioritization

Prioritizing road widening projects that are already on stream needs to be completed, their results studied before moving forward and starting other similar projects. Corridors need to have a meaning and not every road which has traffic becomes a corridor. Certain so called corridors like Sankey road already have alternate roads under widening mode. Redundant corridors should not be built as it dilutes the purpose and focus of corridors

Measurement of traffic also has to be done using PCE units rather than PCU units as the weightage for heterogeneous traffic has to be considered. Passenger Car Equivalent (PCE) is essentially the impact that a mode of transport has on traffic variables (such as headway, speed, density) compared to a single car. Typical values of PCE (or PCU) are:

• private car (including taxis or pick-up) 1
• motorcycle 0.5
• bicycle 0.2
• horse drawn vehicle 4
• bus, tractor, truck 3.5

Congestion charging

Congestion pricing or congestion charges is a system of surcharging users of a transport network in periods of peak demand to reduce traffic congestion. Traffic in central London post congestion charging went down by about 21 per cent, and traffic speeds went up by about 10%.  reports from the cities that have implemented congestion pricing schemes show traffic volume reductions from 10% to 30% as well as reduced air pollution. Singapore ERP pricing has been effective in maintaining an optimal speed range of 45 to 65 km/h for expressways and 20 to 30 km/h for arterial roads.⁵

¹ Carol Jouzatis. "39 Million People Work, Live Outside City Centers." USA Today, November 4, 1997: 1A-2A. As a result of its massive highway construction, the Atlanta area is "one of the nation's worst violators of Federal standards for ground-level ozone, with most of the problem caused by motor-vehicle emissions" (Kevin Sack. "Governor Proposes Remedy for Atlanta Sprawl." The New York Times, January 26, 1999: A14).

² Jill Kruse. "Remove It and They Will Disappear: Why Building New Roads Isn't Always the Answer." Surface Transportation Policy Project Progress VII:2 (March 1998): 5, 7.

³ Stanley Hart and Alvin Spivak. The Elephant in the Bedroom: Automobile Dependence and Denial; Impacts on the Economy and Environment. Pasadena, Calif.: New Paradigm Books, 1993, 122.

⁴ An excerpt from Suburban Nation: The Rise of Sprawl and the Decline of the American Dream by Andres Duany, Elizabeth Plater-Zyberk, and Jeff Speck North Point Press, 2000, pp. 88-94.

⁵ Wikipedia