Highway Lane Research Articles

Colonialism, Postcolonialism, and the Shadow of a New Empire: John Bull's Other Island

Colonialism, Postcolonialism, and the Shadow of a New Empire: John Bull's Other Island Kathleen Ochshorn Seen from a twenty-first-century perspective, Bernard Shaw's 1904 play John Bull's Other Island is remarkably resonant. The Englishman Broadbent and the Irishman Larry Doyle, partners in a Westminster civil engineering firm, travel to rural Rosscullen and come up with a land development scheme. Broadbent's plans are grand in scale: "We'll take Ireland in hand. . . . I shall found public institutions: a library, a polytechnic (undenominational, of course), a gymnasium, a cricket club, perhaps an art school. . . . The round tower shall be thoroughly repaired and restored." 1 Local characters will be tourist attractions. He envisions a Disney-like Ireland, an Irish Epcot. The hilarious battle between the forces of modernization and tradition depicted in Shaw's play is being enacted rather seriously in contemporary Ireland, particularly in the republic. In 2004, a hundred years after John Bull's Other Island was written, six and a half million tourists visited Ireland; it was listed as the number one golf destination in the world. 2 A cultural battle erupted in 2005 over the government breaking ground for a highway near the historic site of Tara, the seat of the high kings. As several Irish scholars wrote in a letter to the Sunday Independent, "Ireland's premier landscape, an icon of our nationhood, is about to suffer an act of vandalism that will see a four lane motorway, a large intersection and undoubted secondary developments obliterate its landscape. All in the name of progress." 3 Colm Toibin noted in the New York Times op-ed section that "[a] place of myth and mystery will look like anywhere. It is called modernization." 4 John Bull's Other Island is a play full of irony, with stereotypes established and undermined, most points of view ridiculed, and little hope offered of a realistic solution to the puzzles of poverty and development. Shaw seems to be the puppet master, hanging over the stage, getting a dark laugh from his absurdist piece. The very occasion for the play, William Butler Yeats's [End Page 180] invitation to Shaw to write a piece for the Irish Literary Theatre, may be the underlying source of much of the irony. As Shaw famously wrote in his 1906 "Preface for Politicians," his play "was uncongenial to the whole spirit of the neo-gaelic movement, which is bent on creating a new Ireland after its own ideal, whereas my play is a very uncompromising presentiment of the real old Ireland" (443). From the outset, this play was built on these contradictory impulses. Asked to commemorate the Irish Revival, which he abhorred, Shaw ended up satirizing the Irish and the English. Tracy C. Davis has contended that Shaw's plays are "a prolonged meditation on the dilemma of colonization, never achieving postcolonialism because institutions of power are not dismantled. . . ." 5 But in John Bull's Other Island, Shaw manages to define and ridicule colonialism; anticipate the nature of a postcolonial Ireland; and imply the difficulties of a free trade, neocolonial economy, where individual and national interests are subverted by the all-powerful forces of development and transnational commerce. Shaw satirizes a particular vision of economic development, largely presented by Broadbent, who also plans to stand for Parliament. The critique prefigures the writings of other colonial and postcolonial writers such as Jamaica Kincaid, whose scathing book A Small Place presents a similar view of a postcolonial economy based on tourism in another former British colony, her native Antigua. 6 Just as Kincaid describes a Hotel Training School built to provide labor for the tourist industry, Broadbent envisions a nondenominational polytechnic to teach efficient development and sort out the best ways to make money. Keegan observes of Broadbent that "[h]e is efficient in the service of Mammon, mighty in mischief, skillful in ruin, heroic in destruction" (606–07). Shaw...

Highways and Forest Fragmentation – Effects on Carabid Beetles (Coleoptera, Carabidae)

We conducted two studies on how highways affect their adjacent habitats by sampling carabid beetles (Coleoptera, Carabidae) in patches of formerly continuous forest next to highways. (1) We sampled carabids at 14 highway intersections near Helsinki, Finland. Each intersection (constructed 2–40 years ago) had two forested patches to study: a remnant (0.5–37.4 ha) and, isolated from the remnant by an intersection lane, an islet (size 0.2–1.8 ha). Pitfall trap catch data (2301 carabids, 25 species) showed that remnants hosted higher catches of three carabid species, and slightly higher species richness, than islets (patch-size effect). Time since intersection construction had no apparent effect on carabids. Traffic volume along the intersection lane determined the assemblage structure of carabids in dry patches, and the abundance of a forest carabid Calathus micropterus. Compared to moist patches, drier patches hosted lower catches of four generalist species; they also had different assemblages of carabids (habitat-type effect). An interaction between patch size and habitat type for a forest generalist Pterostichus oblongopunctatus indicated that the patch-size effect was dependent on habitat type. (2) We examined possible dispersal of carabids among forested patches that were separated by highway lanes in Drenthe, the Netherlands. We released 2696 marked individuals of 10 species, and recaptured 376 using dry pitfall traps. We found no evidence for inter-patch movement for nine forest species, but 22 of 225 recaptured individuals of Poecilus versicolor, an eurytopic open-habitat species, had crossed the highway. Catches of seven forest species were also significantly lower in the road verges, compared to the adjacent forests. These two studies suggest that (i) decreasing patch size negatively affects forest-carabid catch and overall species richness, (ii) habitat type can affect the intensity of the patch-size effect, (iii) carabid assemblages of forest fragments vary with traffic volume (which may be linked with urbanization), (iv) forest carabids rarely cross highways, and (v) open habitats associated with road margins are dispersal barriers for forest carabids.

Discontinuity at edge of traffic jam induced by slowdown

We study the traffic states and jams induced by a slowdown of vehicles in a single lane highway. We use an extended one of the optimal velocity model to take into account the slowdown in a section of highway. The fundamental (flow-density) diagram is calculated. The flow (current) increases linearly with density, saturates at a critical density, and then decreases with density. When the flow saturates, the discontinuous front (stationary shock wave) appears at the end of traffic jam which begins just before the section of slowdown. The position of discontinuous front moves to the upstream with increasing density. It is found that the relationship between the densities holds before and after the discontinuity, while the flow (current) keeps the saturated value. The region map of distinct jams is shown.

Trucking industry preferences for traveler information for drivers using wireless Internet-enabled devices

If truck drivers could use Internet-enabled wireless devices to access traveler information, what type of information would they most want to have? The answer almost surely varies according to the type of trucking operation, location, and many other factors. We analyzed preferences for traveler information from managers of 700 trucking companies to determine how they valued information about such things as locations of freeway incidents and lane closures, port and rail terminal schedules and clearances, delays at terminals train arrivals at grade crossings, weather, and travel times on alternative routes. Using a factor-analytic model with regressor variables, we found clear differences in preferences across types of trucking operations.

Empirical Study of Traffic Features at a Freeway Lane Drop

Traffic was studied upstream and downstream of a bottleneck that arose near a freeway lane drop near London, U.K. using archived high-resolution loop detector data. The bottleneck’s location and mean discharge flows were reproducible from day to day. Further, it is shown that the bottleneck’s discharge flow was about 10% lower than the prevailing flow observed prior to queue formation. Upon bottleneck activation, flow reductions occurring sequentially in time and space marked the passage of the backward-moving shock. Mean shock velocities ranged between 4.8 and 6.4km∕h (3 and 4 mph) as they traveled upstream from the bottleneck. During bottleneck discharge, oscillations arose in the queue and propagated upstream at nearly constant speeds of 17.6–19.2km∕h (11–12 mph). Flows measured at locations downstream of the bottleneck were not affected by these oscillations. These findings were corroborated using data from a freeway lane drop in Minneapolis, Minn. The analysis tools used for this study were curves of cumulative vehicle count, time mean speed and occupancy versus time. These curves were constructed using data from neighboring freeway loop detectors and were transformed in order to provide the measurement resolution necessary to observe the transitions between freely flowing and queued conditions and to identify important traffic features.

Increasing the capacity of an isolated merge by metering its on-ramp

Measurements taken downstream of freeway/on-ramp merges have previously shown that discharge flow diminishes when a merge becomes an isolated bottleneck. By means of observation and experiment, we show here that metering an on-ramp can recover the higher discharge flow at a merge and thereby increase the merge capacity. Detailed observations were collected at a single merge using video. These data revealed that the reductions in discharge flow are triggered by a queue that forms near the merge in the freeway shoulder lane and then spreads laterally, as drivers change lanes to maneuver around slow traffic. Our experiments show that once restrictive metering mitigated this shoulder lane queue, high outflows often returned to the median lane. High merge outflows could be restored in all freeway lanes by then relaxing the metering rate so that inflows from the on-ramp increased. Although outflows recovered in this fashion were not sustained for periods greater than 13 min, the findings are the first real evidence that ramp metering can favorably affect the capacity of an isolated merge. Furthermore, these findings point to control strategies that might generate higher outflows for more prolonged periods and increase merge capacity even more. Finally, the findings uncover details of merge operation that are essential for developing realistic theories of merging traffic.

Vehicle following as backup control schemes for magnet-magnetometer-based lateral guidance

This paper describes the development of the backup vehicle lateral control algorithms for the magnet-magnetometer-based automated lateral guidance. Current vehicle lateral controllers rely on the use of two sets of magnetometers, one under the front bumper and the other under the rear bumper of the vehicle. The magnetometers measure the vehicle's lane following error relative to the magnets buried along the center of the highway lane. The proposed algorithms, based on a laser scanning radar sensor (LIDAR), are backup systems for current magnetometer-based controllers in case of magnetometer failure. The LIDAR sensor measures the vehicle's lateral position relative to its preceding vehicle. The paper considers two magnetometer failure scenarios, i.e., failure in only one set of magnetometers and failure in all magnetometers. Experimental results are presented.

Manipulability-Based Design and Analysis of a Hybrid Manipulator for Highway Applications

This paper presents the design of a parallel/serial manipulator targeted for highway applications. As such, design simplicity is essential. The hybrid manipulator consists of a planar 2-link parallel mechanism coupled to a translational mechanism. Detailed kinematics are employed to understand the resultant workspace, feasible paths, and manipulability. Based on the analysis, optimal design parameters are selected using a manipulability-based approach to allow for dexterous operations over a full highway lane width. A simple but effective redundancy resolution method is developed to partition motion between the two mechanisms. The design method is applied for a representative highway maintenance task.

Variation in Freeway Lane Use Patterns with Volume, Time of Day, and Location

Lane flow data for five extended freeway segments in the San Diego, California, area were used to examine the effects of freeway and ramp volumes on lane flow distributions and to explore the extent to which these relationships vary by time and location. The proportion of the flow using particular lanes varies significantly with the freeway volume but not with the on-ramp volume. Relationships between freeway volume and the proportion of flow in particular lanes vary significantly by time of day, with flows in different lanes more nearly equal in midday periods than before the morning peak period or after the evening peak period. Such relationships are relatively similar for different days at the same location and different locations within the same extended freeway section but are quite dissimilar for different sections. As a general rule, the proportion of flow in the median lane increases with increasing volume and is greater than that for other lanes in congested flow and high-volume uncongested flow; however, in some cases it increases continuously with increasing volume, and in others it increases up to a point and then decreases. The major implications for behavioral theories of traffic flow are that lane use behavior varies with driver population characteristics and that in making lane use decisions, drivers are sensitive to both speed and vehicle spacing.

Variation in Freeway Lane Use Patterns with Volume, Time of Day, and Location

Lane flow data for five extended freeway segments in the San Diego, California, area were used to examine the effects of freeway and ramp volumes on lane flow distributions and to explore the extent to which these relationships vary by time and location. The proportion of the flow using particular lanes varies significantly with the freeway volume but not with the on-ramp volume. Relationships between freeway volume and the proportion of flow in particular lanes vary significantly by time of day, with flows in different lanes more nearly equal in midday periods than before the morning peak period or after the evening peak period. Such relationships are relatively similar for different days at the same location and different locations within the same extended freeway section but are quite dissimilar for different sections. As a general rule, the proportion of flow in the median lane increases with increasing volume and is greater than that for other lanes in congested flow and high-volume uncongested flow; however, in some cases it increases continuously with increasing volume, and in others it increases up to a point and then decreases. The major implications for behavioral theories of traffic flow are that lane use behavior varies with driver population characteristics and that in making lane use decisions, drivers are sensitive to both speed and vehicle spacing.

Using Narrow Freeway Lanes to Mitigate Transportation-Related Problems

Congress is considering funding dedicated truck lanes. It might make more sense to fund dedicated small-vehicle lanes for urban commuter traffic. These small-vehicle commuter lanes (SVCLs) would help mitigate many of today’s traffic-related problems. They would be less expensive to build and require smaller rights of way and thus save taxpayer funds. The available funds will build more traffic lanes that will ease traffic congestion. SVCLs would also nurture the use of small vehicles, which would mitigate this country’s growing energy concerns.

Risk Analysis of Freeway Lane Closure during Peak Period

This paper examines risks associated with peak period lane closure during construction or maintenance work on urban freeways. In accordance with recently implemented policy by the Colorado Department of Transportation, lane closure would be allowed if reserve capacity were available. A relatively minor accident in the work zone caused substantial delays during the peak period that virtually paralyzed traffic in the Denver, Colorado, metropolitan area. This occurrence caused reexamination of the existing lane closure policy. Generally speaking, if a contractor is allowed greater flexibility in establishing work schedules, including the ability to work through peak periods, a lower bid can be expected. This paper compares savings in the cost of construction related to allowing lane closure during peak periods with the cost of potential incident-related delays in the framework of a quantitative risk analysis.

Risk Analysis of Freeway Lane Closure During Peak Period

This paper examines risks associated with peak period lane closure during construction or maintenance work on urban freeways. In accordance with recently implemented policy by the Colorado Department of Transportation, lane closure would be allowed if reserve capacity were available. A relatively minor accident in the work zone caused substantial delays during the peak period that virtually paralyzed traffic in the Denver, Colorado, metropolitan area. This occurrence caused reexamination of the existing lane closure policy. Generally speaking, if a contractor is allowed greater flexibility in establishing work schedules, including the ability to work through peak periods, a lower bid can be expected. This paper compares savings in the cost of construction related to allowing lane closure during peak periods with the cost of potential incident-related delays in the framework of a quantitative risk analysis.

Resistance to Freezing and Thawing Cycles and Scaling Resistance of Very High Early Strength Concrete

Abstract A very high early strength portland cement-based concrete (VHES) is used to prevent long closures of highway lanes by completing any necessary repairs overnight. This technology has been embraced by several DOT agencies, including those in areas where the concrete will be subjected to freezing and thawing cycles. Flexural strength of VHES concrete is the critical parameter to permit traffic flow without damage to the concrete. It is possible to produce air-entrained rapid repair concrete, but this places higher requirements on the mixture proportions to overcome strength reduction caused by the presence of air. This article presents data showing that it is possible to attain the necessary strength and achieve adequate resistance to freezing and thawing cycles. The evidence presented includes accelerated testing using ASTM C 666, Procedure A, and scaling resistance using ASTM C 672. Additional evidence is presented showing that VHES concrete of low w/c can be durable with larger than acceptable spacing factor levels or without air entrainment.

A risk-based approach for the design of rock slopes subject to multiple failure modes—illustrated by a case study in Hong Kong

The widening of the Tuen Mun Road highway in Hong Kong involved construction and subsequent operation in an area of steep rock slopes above a heavily trafficked six lane highway. A risk-based approach to slope design was required by the authorities. The approach that was developed is described in detail and includes consideration of risk acceptance criteria, consequence analysis, effects of traffic characteristics, likelihood of slope failure and overall risk and risk allocation. Based on statistical data for slope failures in Hong Kong, world-wide data on dam failures and some engineering judgement, a relation was estimated between annual probability of slope failure and design factor of safety. The implementation of the design involved allocation of acceptable levels of risk to different sections of slope and different modes of slope failure such that the summation of all risk was less than an expected fatality rate of 0.01 deaths per year per 500 m section of slope. This level of risk was determined in relation to objective standards for industrial facilities generally as defined by Hong Kong Planning Guidance criteria (Hong Kong Planning Standards and Guidelines, Hong Kong Planning Department, 1996 (Chapter 11)). These risks were converted into design factors of safety using the likely numbers of failures per mode and per section (more possible failures means that each possible failure location requires a higher factor of safety to achieve the overall risk objectives). Required design factors of safety from this approach were typically in the range 1.2–1.8 compared with a normal requirement in Hong Kong of 1.4.

Modeling of Traffic Flow of Automated Vehicles

With the development of near term automatic vehicles following concepts such as intelligent cruise control (ICC) and cooperative driving, vehicles will be able to automatically follow each other in the longitudinal direction. The modeling of traffic flow consisting of such vehicles is important for analyzing the effects of vehicle automation on the characteristics of traffic flow and for suggesting macroscopic control strategies to improve efficiency. Such analysis may also suggest ways for modifying the vehicle control characteristics in order to improve the macroscopic behavior of traffic. In this paper, we developed a mesoscopic and macroscopic model that describes the automated traffic-flow dynamics in a single highway lane. The mesoscopic model describes the speed and density continuously in time and space and at the same time retains the microscopic characteristics of traffic flow. The macroscopic model describes the average speed and density at each section of the lane and at each point in time. Even though the macroscopic model does not retain the microscopic characteristics of the vehicular traffic, computationally it is much simpler than the mesoscopic one. Simulations are used to demonstrate the effectiveness of these models in describing traffic-flow characteristics. The developed models indicate some similarities, but also some fundamental differences with existing traffic-flow models for manually driven vehicles.

THE LANE EXPANSION EFFECT OF THE TOLLBOOTH SYSTEM ON THE HIGHWAY

In this paper, we investigate the lane expansion effect of the tollbooth system. To this end, two typical values of randomization probability p:p=0.5 and p=0.1 are chosen. It is shown that for p=0.5, the full capacity of the single lane highway can be restored. However, for p=0.1, our simulations show that the full capacity of the single lane highway cannot be restored due to the existence of the merge section in the lane expansion section. Moreover, we have investigated the dependence of road capacity on the length of lane expansion section as well as the effects of the positions of the tollbooths in the lane expansion section under different values of p.

Tool to Evaluate Safety Effects of Changes in Freeway Traffic Flow

This research involves the development of a tool that can be used to assess the changes in traffic safety tendencies that result from changes in traffic flow. The tool uses data from single inductive loop detectors, converting 30-second observations of volume and occupancy for multiple freeway lanes into traffic flow regimes. Each regime has a specific pattern of crash types, which were determined through nonlinear multivariate analyses of over 1,000 crashes on freeways in Southern California. These analyses revealed ways in which differences in variances in speeds and volumes across lanes, as well as central tendencies of speeds and volumes, combine in complex ways to explain crash taxonomy. This research may provide the foundation to forecast the crash rates, in terms of vehicle miles of travel, for vehicles that are exposed to different traffic flow conditions.

Freeway safety as a function of traffic flow

In this paper, we present evidence of strong relationships between traffic flow conditions and the likelihood of traffic accidents (crashes), by type of crash. Traffic flow variables are measured using standard monitoring devices such as single inductive loop detectors. The key traffic flow elements that affect safety are found to be mean volume and median speed, and temporal variations in volume and speed, where variations need to be distinguished by freeway lane. We demonstrate how these relationships can form the basis for a tool that monitors the real-time safety level of traffic flow on an urban freeway. Such a safety performance monitoring tool can also be used in cost-benefit evaluations of projects aimed at mitigating congestion, by comparing the levels of safety of traffic flows patterns before and after project implementation.

Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks.

A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of "weak" and "strong" congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught at the upstream bottleneck (the catch effect). MSP, WSP, or wide moving jams first emerged at the downstream bottleneck induce diverse patterns at the upstream bottleneck. The onset of congestion at the upstream bottleneck can lead to an intensification of congestion at the downstream bottleneck. This causes a change in the pattern type and/or the pattern features.