Unsuccessful bids: Coefficient of variation of bids as indicator of project risk

Although unsuccessful bids are usually discarded once the bids are opened under the typical lowest-price sealed-bid project award auction environment, considering efforts and resources expended by responsive and responsible bidders, it is likely that not only a successful bid but also unsuccessful bids can convey important information about the project at hand. This article documents an effort to answer the question that whether projects that receive more dispersed estimates at the bidding stage are more likely to experience greater project cost changes. Taking collective intelligence as the theoretical framework, a total of 210 projects conducted by the Ohio Department of Transportation between 2008 and 2018 were analyzed to investigate the relationship between the coefficients of variation of bids and project final costs. It was found that large projects with above-average coefficients of variation of bids showed greater deviations from original award amounts than large projects with below-average coefficients of variation. The finding enables project owners to study the projects before execution by recouping valuable insights from the community of bidders on the possibility of greater project cost changes faced by the planned projects without complex and mathematically rigorous models.

Viewing Ground-Mounted Diagrammatic Guide Signs Before Entrance Ramps at Night: Driver Eye Scanning Behavior

The driver eye scanning study is part of a larger study conducted for the Ohio Department of Transportation to evaluate the effectiveness of ground-mounted diagrammatic guide signs placed before entrance ramps at highway freeway interchanges. This nighttime study investigated driver eye scanning behavior while approaching ground-mounted diagrammatic guide signs placed before entrance ramps. Six highway-freeway interchanges were selected in the Greater Columbus, Ohio, area for placement of the diagrammatic signs in the field. Subjects were six unfamiliar drivers, between the ages of 22 to 42. Two diagrammatic signs were located at each of the six interchanges, .5 mi (805 m) and .25 mi (402 m) before the last point of the gore, where a driver can still gain access to the correct freeway entrance ramp. Driver eye scanning behavior measurements were recorded at night to determine if the presence of the diagrammatic signs elicited an excessive number of eye fixations or was visually distracting to the drivers or both. The results indicate that the diagrammatic signs are not looked at excessively often or excessively long. The average look numbers and average look duration times indicate a normal and reasonable level of information acquisition processing employed by the drivers. These values agree with those previously obtained for regular traffic signing determined in previous eye scanning studies. Ground-mounted diagrammatic signs on multilane arterials in advance of highway freeway interchanges were not demonstrated to unduly distract drivers and detrimentally affect a driver’s looking behavior.

Nighttime Expert Panel and Photometric Evaluations of Unlighted Overhead Guide Signs

A nighttime field evaluation of four different retroreflective overhead-sign sheeting combinations (ASTM D4956 beaded Type III legend on beaded Type III background, Type IX legend on beaded Type III background, Type IX legend on Type IX background, and Type VII legend on beaded Type III background) was conducted on a section of US-30 near Mansfield, Ohio. The test-material combinations were compared when lighted and unlighted (illuminated by low-beam headlights only). Twelve Ohio Department of Transportation engineers and technicians served as evaluators, riding the test loops in 2002 Dodge Caravans. The white Type IX legend on green-beaded Type III background sheeting combination received the highest evaluation scores for appearance, conspicuity, and legibility. The scores for the Type VII legend on beaded Type III background signs were only slightly lower in all three categories. The Type IX legend on Type IX background combination received slightly lower evaluation scores, and the beaded Type III legend on beaded Type III background combination received the lowest evaluation scores. The same signing material combinations were also photometrically (luminance and luminance contrast ratio) evaluated under low-beam illumination at selected approach distances from 200 to 1,000 ft (61 to 305 m) using a 1984 Peterbilt truck, a 2002 Chrysler Town and Country minivan, and a 2002 Toyota Camry sedan, both when lighted and unlighted (low beams). Unlighted overhead signs made with either the white Type VII or the Type IX legends on green-beaded Type III backgrounds provide nighttime motorists with adequate appearance, conspicuity, and legibility.

Effectiveness of Ground-Mounted Diagrammatic Advance Guide Signs for Freeway Entrance Ramps

This study investigated the effectiveness of ground-mounted diagrammatic signs in the context of urban multilane arterials leading to freeways. Six highway-freeway interchanges were selected in the greater Columbus, Ohio, area for installation of the diagrammatic signs in the field. The primary measure of effectiveness was the distance at which unfamiliar drivers driving in the wrong lane changed lanes. A total of 21 and 19 test drivers unfamiliar with Columbus roads were recruited for an evaluation before and after installation of the diagrammatic guide signs. This evaluation with unfamiliar test drivers showed that drivers were able to execute a needed lane change earlier when diagrammatic signs were provided. Combining all six sites and looking at the 50th (377 m before, 819 m after) and 85th percentile (203 m before, 601 m after) lane change distances, an increase by a factor of 2.2 to 3.0 between the after and before condition was observed. In addition, a panel of 13 Ohio Department of Transportation and FHWA evaluators visited the six interchange sites and provided their input and opinions on the use of diagrammatic signs. The majority of the evaluators fully embraced the idea of diagrammatic signs. It is suggested that such signs should be used on multilane arterials in advance of highway–freeway interchanges in addition to preexisting guide signs (trailblazer assemblies), in cases in which the cost of overhead span-type sign bridges cannot be economically justified and additional advance guidance information to motorists is highly desirable.