This paper explores the research under way in developing an autonomous vehicle command and control system; it also explains the means by which guidance is maintained and in‐yehicle navigation system are integrated into the vehicle control system. This system integration feature allows the vehicle to operate in a mixture of both automatic and manually controlled vehicles. The unique features investigated in this research include the relationship between the on‐board control system and other nonautomated automobiles; the efficiency and usefulness of the new navigation concept; and the system approach to interactive linking of the in‐vehicle control system with three transportation modes: (1) Other automated vehicles; (2) other nonautomated vehicles; and (3) the public street and/or freeway control system. Further discussed, in system descriptive terms, is the actual in‐vehicle control system, in‐pavement transponders, a flux gate compass, an automatic vehicle location reader, and lateral/longitudinal radar proximity devices. The text also illustrates the logic of the on‐board control system including the development of the various signal conditioning devices and local slave computer systems required to drive the main management/navigational computer system.

This paper explains how the new technologies of roadway electrification and automation can be applied to help alleviate the severe transportation/environmental/energy problems facing our major metropolitan areas. The necessity of a complete system solution that encompasses these three problem areas simultaneously is emphasized. While the roadway‐electrification technology is targeted at the environmental and energy problems, the automatic steering and longitudinal control technologies serve to enhance mobility and safety in our urban motor transportation system. The vehicle control technologies offer the potential for dramatic increases in roadway capacity, which can significantly reduce travel times in congested urban regions. The significant synergism among the three technologies means that coordinated development and implementation will be significantly more beneficial than an approach that focuses on only one or two of the three technologies.

For vehicular communications in automated transportation systems, a very important problem is to maintain high‐quality broadband communications at all locations. Furthermore, to achieve the automated navigation of vehicles, two pieces of information are of great necessity: the knowledge of the real speed of the vehicle and its absolute position along the track. Using a slotted specialized microwave waveguide, a new concept has been developed in France that allows the simultaneous transmission of several TV voice channels and high‐capacity numerical transmissions. It also enables a high‐precision speed measurement without mechanical contact with the ground. Lastly, using different orientations of the slots, a pseudo‐random sequence is read while the vehicle moves along the track, so it is possible to conclude continuously on its absolute position. Working in the 2.4–2.5 GHz industrial, scientific and medical (ISM) band with low radiated power $\left(<\mathrm{dBm}\right)\text{,}$ the system exhibits a 100 MHz bandwidth with limited administrative problems. Its mechanical dimensions enable a rugged construction of the waveguide. Finally, a fairly low linear automation is obtained at this frequency (13–15 dB/km), so that a minimum number of repeaters is required.

In Japan, the Public Works Research Institute of the Ministry of Construction has started the development of a road‐automobile communication system (RACS) under a joint research program with 25 private companies. The subject of the development project is to establish the following systems using road‐side transmitting beacons: a navigation system, an information system, and an individual communication system. The radio communication of this system is unique compared with current radio communications systems. Field experiments on navigation and information have been carried out since March 1987. A digitized road map, 93 beacons (including 2 information beacons), and 11 in‐car devices were prepared for this field experiment. Through these experiments, it has been confirmed that RACS is fully practicable for aforementioned navigation and information systems.

Population growth, continuing suburbanization, and higher labor‐force‐participation rates, combined with a virtual halt in new freeway construction, have led to rapid increases in traffic congestion in the U.S. This congestion is costly; for example, the cost of highway congestion in the Los Angeles region is estimated to be $3.6 billion per year. Roughly half of this congestion is estimated to be caused by incidents, and 63% is on freeways. In the future, planners project that congestion will increase dramatically and that the proportion of delay on surface streets will increase, as congestion spreads. Automated freeways have been proposed as a solution to urban traffic congestion. Paper describes the staged development of automated urban freeways and then suggests a series of research topics related to the major policy issues of road capacity, air quality, noise, safety and liability, cost and equity, privacy, and organizational complexity. These difficult questions should be resolved before public acceptance for the technology is sought. Policy research on these matters should be carried out before or at the same time as the technology is being developed.

Nontechnical concerns must be overcome before investors will give serious consideration to the large expenditures required for the development of smart vehicle‐highway control systems. The most important step would be the development of joint public‐private initiatives to create incentives for the U.S. industry to actively pursue research and development of these (and other) socially beneficial products. Fortunately, there is increasing evidence that these concerns will be addressed and that in due time the nation will be able to take advantage of smart vehicle‐highway systems.

Corps of Engineers accelerated traffic tests were reanalyzed to develop a structural deterioration model for airfield pavements. Test‐back performance was measured in terms of structural condition index varying from zero to 100. This index is derived from the pavement‐condition index. Pavement performance is predicted in terms of a structural condition index from the pavement's layered elastic stresses, flexural strength, and number of traffic loads. This model was compared to other design criteria, unfailed test sections, and three failed airfield pavements and gave reasonable agreement. This model only accounts for damage from fatigue loading, and there are a number of other potential pavement‐distress modes that it does not include. Each of these distress modes needs to be evaluated separately.

Current airfield overlay design generally uses empirical methods developed in the 1940s and 1950s. This paper presents a mechanistic overlay design procedure based on layered elastic theory as an alternative to the empirical design procedure. The layered elastic model is capable of analyzing layered structures with different material properties and interface conditions. It is also compatible with many current evaluation techniques using falling weight deflectometers. This mechanistic design approach includes the effects of fatigue and structural damage to the base pavement before overlay, progressive cracking of the base pavement after overlay, and substandard load transfer at joints. The proposed design procedure was checked against the results of the accelerated traffic tests originally used to develop the empirical overlay design equations, and comparative designs were also made using the proposed design procedure and the empirical equations. The proposed procedure generally gave good and reasonable comparisons with traffic test data, but the quantity of overlay test track data is limited. This analysis found that the current unbonded overlay equation is conservative; however, the partially bonded equation is not.

Aviation growth over the last two decades has caused traffic volumes at many airports to attain near‐capacity levels. Demand management systems have been used to increase throughput and alleviate congestion where practical. However, airports continue to be increasingly congested. Due to restricted land availability as well as environmental and community concerns, the potential for airport expansion is often limited, and airport authorities increasingly face the prospect of relocating airports. Obviously, the ability of the airport to serve its market is affected by such a relocation. This paper examines the importance of airport proximity as well as the effects of level‐of‐service factors on alternate airport choice. Disaggregate modeling techniques were used in the identification of factors affecting the choice of alternate airports in a limited geographical area (northern New Brunswick, Canada). The research demonstrates the significance of level‐of‐service variables in the airport‐choice decision. Air travelers had a strong preference for jet aircraft and were willing to travel significant ground distances in order to reach an airport offering jet service. The analysis results clearly show that this was the single most important variable in the airport‐choice decision. Other significant level‐of‐service variables were flying‐time difference and whether a direct flight to destination was available.

Applications of a microcomputer‐based Monte Carlo simulation model for analyzing the impact of different operating strategies (e.g., additional time points, bus priority, and demand profile) on two measures of quality of service of fixed‐route bus services are discussed. Two fundamental service quality measures, i.e., headway variations and the degree of adherence to schedules (on‐time performance), are considered. It is shown that simulation can provide the necessary insight needed for planning bus‐service operations when journey speeds, passenger demand, and route characteristics are uncertain. For instance, it is demonstrated that when the interstop journey speed of a route is normally distributed, the deterioration in on‐time performance with respect to dispatch time is a direct function of the variance of the distribution. There is also certain limit to the number of time points that can have a positive influence on headway variations and on‐time performance. This paper describes the use of the simulation model for identifying the optimal number of time points and for assigning them to the route to achieve the desired on‐time performance level.

Fifty‐nine urban transportation professionals replied to a survey on the approriate strategems to be employed in preventing severe traffic congestion. Personal philosohies on the engineer's past role in the problem's development are examined as well, and these responses have been classified by employment sector. These professionals seem to agree on very little, but do seem to perceive the problems involved. Respondents are polled in particular on approaches now being taken in the private sector for new development, wherein the developer, the owner, and the tenants are committed to a role in solving the area's future transportation problems. Much misinformation and unawareness seems to exist about such devices as impact fees and trip reduction ordinances. Great caution is exhibited, especially about the general legalities of these new strategies. Traditional tools and approaches were more favored. The various transportation strategies are ranked by respondents as to potential in combatting congestion.

The principal sources of error in the trip patterns estimated by cross‐sectional‐type trip distribution models are their inability to capture the spatial evolution of urban areas and the socioeconomic biases in the spatial distributions of resident labor force and jobs. The paper describes a recursive‐type activity allocation‐transport demand model that address some of the model deficiencies. The paper describes the spatial evolution of the Toronto, Ontario, Canada, urban region and shows that the growth and change in commuting demands are strongly influenced by the socioeconomic biases in the distributions of labor force and employment. An activity allocation‐transport demand model is introduced; it estimates the employment in each zone in each of seven industry sectors, then converts these into jobs in each of eight occupation groups. The labor force living in each zone is calculated from the household structure estimated for each zone. Trip distribution patterns for each occupation group are estimated using a two‐level approach that combines the advantages of the Fratar‐type and doubly constrained gravity models.

Elevated steel water pipelines may be subjected to transverse and vertical seismic forces, and should be designed to withstand these forces safely. A specific elevated steel water pipeline is studied using a linear computer program that incorporates the response spectrum approach for seismic analysis. Two means of pipeline support are studied and compared: a steel moment-resisting frame system and a steel vertical truss system. Preliminary design of the individual supports is completed using an approximate lateral-force procedure. The bending moment in the pipeline is then investigated, as well as the lateral forces imparted to the support structures, using the response spectrum approach, with modifications for damping and ductility. Results indicate that the equivalent lateral-force procedure does not prove satisfactory for this particular pipeline. In addition, the vertical truss method of support results in a consistently lower bending moment in the pipeline than does the moment-resisting frame method of support.