^he Highway Interchange Land-Use Problem AVID R. LEVIN, Chief, Division of Highway and Land Administration, U. S. ureau of Public Roads, Washington, D.C. OFFICIALS and technicians who have been concerned with the provision and improve- ent of public highway accommodations have sought to foster intercommunication—by eans of the vehicle and its occupants—between the several regions of the nation, a- ong the States, between major areas within each State, between the portions of a ven metropolitan area, and even between a particular place or person on one street id a particular place or person on another street. This has been achieved by a vari- V of highway facilities grouped in highway systems. Each functional system serves accommodate a particular segment of the economy and need for vehicular travel. The particular type or system of highways with which this paper is concerned might identified as the expressway system, characterized by some degree of access con- 3l. It includes the Interstate System, but is by no means limited to it necessarily. One of the important features of the expressway is the interchange or the grade paration structure that facilitates the entrance or exit of vehicles to or from the pressway, from or to the Intersection of adjacent roads or streets in a particular :inity. It Is by means of the expressway interchange that the Inherent utility and periorlty of this modern highway facility comes into play. It is only by the means of ! interchange that the ultimate purpose of e^qpressway travel, between origin and stination, is finally achieved. Accordingly, the importance of the e3Q>ressway inter- mge cannot be overemphasized, in terms of the part it plays in functionalized ve- ••.ular travel. The importance of the interchange is revealed by some simple data relating highway lies to numbers of interchanges. It is estimated that there could be as many as , 000 interchanges on the 41,000 miles of the Interstate System. For obvious reasons, lir frequency in urban areas will be greater than in the rural regions. LAND-USE PROBLEM AT THE INTERCHANGE Each interchange is designed in accordance with established engineering and design teria, and each interchange ramp has a given design capacity. The criteria and lign capacities used are based on traffic that could reasonably be expected to ac- •nulate as of 1975, and other factors. In this connection, hi^way officials have n directed to anticipate the future at least to this extent by the Congress, in Title lln meeting this responsibility, the highway official has traditionally sought to do best that modern highway technology makes possible. Highway officials cannot !see the future, except to a limited extent—they are technicians and not magicians, •eover, they have generally executed their assigned duties without encroachment he prerogatives of pubUc officials in other fields of public endeavor, t is in this connection that the land-use problem at the interchanges arises. In ns of a given interchange, the highway official will assume that certain land-use elopments will reasonably occur in the areas that will be tapped by that inter- nge. He designs the Interchange on that basis. In a number of instances, parti- irly in urban and suburban areas, and where other factors encourage the location and uses Involving substantial traffic generators, almost before the pavement is on an interchange ramp, several huge industrial plants, a regional shopping er, a huge housing center, a complex of motels and restaurants, and other large Jflc generators will be located next to the entrance or exit terminal of the inter- Bige, literally at the ends of the ramp or in the general vicinity. More often than there are few, if any, local public restraints on such private activity. After a while, the unanticipated, additional traffic load which these generators create fre• quently will cause the ramp to break down functionally, because the design capacity of the ramp has been exceeded. This situation creates the problem at hand today, in connection with many highway interchanges. It is the problem to which this paper and this symposium are address• ed. Other papers this morning will dwell on the legal aspects of possible solutions; | on a quantification of the supply and demand for land for the principal types of land uses; on the pressures and needs for road users accommodations at the points of interchange; and on other aspects. This paper discusses the possibilities for reason• able controls in terms of their potential effectiveness, cost and administration. LAND-USE DEVELOPMENT FROM A PRIVATE POINT OF VIEW It is not difficult to infer that there is much at stake, if reasonable and intelligent solutions to the problem of the highway interchange are not developed. At stake is not only the functional well-being of the entire Interstate System in terms of the traf• fic service it is designed to render, but also in terms of the tremendous investment public funds in these modem highway accommodations. Experience to date indicatesl that each interchange can represent an investment ranging from $129, 000 to over $2, 000, 000. An average of such cost for 14,000 interchanges, more or less, on the| Interstate System will aggregate into the billions. Neglect of solution of this problem can also mean that additional millions of doUail of private capital can also turn out to become bad investments. In this connection, the bypass analogy seems pertinent. In the past, highway of• ficials have built highway bypasses to provide for through traffic service on a route that had become cluttered with all sorts of roadside enterprises. When traffic was thus diverted to the new route, the businesses on the old route that may have suffere as a result of such diversion were not and could not legally be compensated even for any actual damages. After the new route was opened to traffic, new private installa• tions traditionally would again engulf the new highway route, unless it happened to be of the ejg>ressway variety. Then, a bypass would be built to bypass the bypass, and so on. This is merely to point out that private enterprise itself has an important stake iil establishing itself along highways of modem design and in such a manner that its venture capital is not Impaired long before the physical plant wears out, only becausl of the functional obsolescence of the highway. It is to the advantage of private ventuf capital, as well as of the public at large, that interchange areas be so designed, and! land uses in the vicinity appropriately placed in relation to the access facilities, so that both can thrive for years to come. If the public facilities break down physicall]i| or functionally, the private adjacent uses stand to lose as heavily as the public, if not more so. It is not suggested, of course, that private land uses in the private areas beyond the interchanges be prohibited entirely. The Interstate System is not being built fori it to become a museum piece, encased in glass. The system is not an end in itself,f but a means to an end. It is beii^ designed and built to serve through traffic, prival land use, and private enterprise in a larger sense. To serve this end most effectivl ly, the most intelligent means to create order out of what otherwise is sure to be ctm must be devised immediately. TIMING OF SOLUTIONS Because it might be another five years or more, before the problem really gets be acute, why not wait vintil then for corrective measures? The answer is simple enough: If the problem is upon us, it will be too late to do| anything effective about it. In another five years, the land use development will al• ready have taken place and it will be largely academic as to what can be done at thai time. The time to act is now. THE INTERCHANGE ON THE TOLL ROAD AND ON THE FREE ROAD In seeking effective solutions to the interchange-land use problem, the toll road lay provide some limited experience. However, some significant legal, design and inancial differences are involved, and these may seriously invalidate the analogous ature of the toll road, in terms of the "free" portions of the Interstate System, at iast. These differences are several. For one, there are substantially fewer interchai^e )ints on toll roads. As one would expect, there are significant differences between e rural and urban portions of both toll roads and free roads. For 1, 806 mi of toll >ad in rural areas, the average interchange spacing is 13.4 mi; for 461 mi of toll >ad in urbanized areas, the average interchange spacing is 2. 6 mi. For 33, 513 mi free road in rural areas, the average spacing is 4.5 mi; for 4, 622 mi of free road urban areas it is 1.1 mi. These national avers^es, of course, obscure significant gional and State differences in interchange spacing, and, accordingly, should be ^ed with the greatest of care. Additionally, certain types of private enterprises catering to the travelers are rmitted in designated areas along toll roads; whereas, they are prohibited by Federal |w and regulation from the Interstate System. ^ The first opportunity these types of iterprises have to establish themselves, accordingly, would be at the interchange ints of the system. Finally, by far the vast portion of the existing toll road mileage has been in the ral areas, while a substantial portion of the Interstate mileage is urban or suburban nature. At least 5, 500 mi are designated as urban, and an additional mileage will found in the suburban or rurban areas.