Master of Science / Department of Civil Engineering / Sunanda Dissanayake / Speed management has been a challenge, particularly in places where high-speed highways pass through. Due to high rate of fatalities and low budgets available, it is therefore necessary to identify low-cost effective approaches in reducing speeds. Optical Speed Bar (OSB) treatment is one such technique. This research makes an attempt to evaluate the effectiveness of OSBs in reducing approach speeds on two-lane, rural highways approaching small communities. Speed data were collected and analyzed “before” and “after” periods at five sites. Effectiveness of OSBs was evaluated using changes in mean and 85th percentile speeds under different categories by considering all vehicles, vehicle classification (two axles vs. more than two axles), day of the week (weekdays vs. weekends), and time of day (daytime vs. nighttime), as well as proportions exceeding posted speed limit, using t-test mean speeds, F-test for analysis of variance, and Z-test for proportions of vehicles exceeding posted speed limit between “before” and “after” datasets. Even though motorists were found to slow down on the approaches, in response to speed zones, speeding was noted. “Before” speed data indicated higher speeds than desired at the sites. The 85th percentile speeds were between 50 and 63 mph while the posted speed limits on the approaches were 45 mph at four sites, and the 85th percentile speed was about 42 mph at one site with an approach posted speed limit of 30 mph. The “before” degrees of noncompliance were up to 90 % of free-flowing vehicles at the sites. Speed data analysis showed significant reductions in speeds at ends of OSBs at four test sites. Mean and 85th percentile speeds and standard deviations were found reduced in the after periods. Percent reductions in mean speeds were between 1.2 and 8.2 %, with 85th percentile reductions between 3.2 and 8.9 %. At one site, no notable change in mean and 85th percentile speeds occurred at the end of OSBs, but significant increases in standard deviations were noted. Speed reductions were higher for two-axle vehicles, during the daytime and on weekdays with few exceptions. Results of the study showed, as other previous studies did, OSBs may have some minor effects on vehicle speeds. The study provides an indication that it may be possible to create safety improvements as result of using OSBs on the approach to a rural community. However, magnitude of speed reductions was generally small, though the reductions were statistically significant at the 95% confidence level. Because of the non-consistence of the magnitude of speed reductions at the test sites, no conclusion can be drawn as to how much OSB treatment reduced speeds. These results were based on “after” periods up to five months. Therefore, further study would be required to determine whether these safety improvements are sustained over an even longer time period. Even though minor speed reductions occurred, speeds observed at the sites were still higher than the posted speed limits, indicating OSBs were not effective enough in providing the desired speed limit compliance. Additional studies would be helpful to identify combinations of countermeasures, for instance OSBs and other techniques, effective in providing speed limit compliance.

In the United States, speeding is considered to be a contributing factor in about 30 percent of fatal crashes (US DOT, 2000). In an attempt to reduce speeds on roadway segments where speed is considered to be a safety concern, various low cost countermeasures have been investigated. Such countermeasures include pavement markings that give a psychological appearance of narrowing and/or increasing speed have been considered as a relatively low-cost treatment. Perceptual cues are one potential method of influencing motorists to slow down, and ultimately, to save lives. These perceptual techniques might be useful at lowering speeds in a variety of driving situations such as work zones, curves, roundabouts, and toll plazas. Evaluations are required in order to determine the effectiveness of these various treatments at reducing speeds. This research project explored several possible perceptual countermeasures to try on the approaches to curves for reducing speeds. It was ultimately decided to evaluate the effects of peripheral transverse lines in reducing speeds. Although there have been some limited evaluations of peripheral transverse markings in previous studies, no significant field evaluation has been performed and a recommended design for the markings has not been discussed. The projected results of the research effort is to determine pavement marking treatments with a high probability of success at reducing speeds, develop and design peripheral transverse markings based on site considerations, determine the effectiveness of the markings in the field, determine optimal pavement marking design using a driving simulator, and use a controlled research environment to finalize the design. This dissertation contributes to the body of knowledge on speed reduction research through the development of low cost speed reduction strategies, the design of peripheral transverse lines for varying geometric conditions, evaluation of these treatments in the field, in the simulator, and on a controlled roadway, and to finally compare the benefits of each of the evaluation approaches. In the field, peripheral transverse lines spaced at a frequency of 4 bars per second were evaluated in New York, Mississippi, and Texas. The markings were applied on approaches to curves in both rural and urban environments on both multi-lane and two-lane roadways. The authors concluded that overall, the pavement markings reduced speeds up to 59% compared to the baseline in the short term and 24% in the long term on overall vehicle speeds. When evaluating design alternatives of peripheral transverse markings, a follow-up study was performed and compared baseline conditions to markings spaced at a constant interval, exponentially closer, at two bars per second, and at four bars per second. The peripheral transverse lines were effective in reducing centerline encroachment; however, the results were inconclusive as to which particular marking spacing pattern was most effective. There was a large amount of variability in driving speeds using the driving simulator which made it ineffective at comparing designs. The third evaluation was performed at the Virginia Tech Smart Road in which reductions in speed were compared to the baseline at two locations. While one curve had large preview distances and no effect due to the treatments, speed reductions on a freeway ramp type of curve resulted in a speed reduction 42% greater than the reduction in the baseline condition. There are several advantages and disadvantages to evaluations in the field, simulator, and at a controlled research setting which are summarized in this dissertation. Overall, all three have potential of looking at different elements, but it was determined that variability when measuring speed in the driving simulator makes it more challenging as a tool for measuring speed reductions. / Ph. D.

Värdet på ett företag kan variera beroende på vilken nytta det kan anses ha för olika individer.Att finna ett värde på ett företag som är fullkomligt sant, objektivt eller obestridligt är därför iprincip en omöjlighet. Resultatet av en företagsvärdering bygger i stor utsträckning påantaganden och subjektiva uppskattningar vilket påverkar bedömningen, men även syftet ochvilken typ av företag det gäller har betydelse för värderingen.Värdering av såväl onoterade som noterade företag bygger på samma modeller och principer,men det är förknippat med större osäkerhet och svårighet att bedöma ett onoterat företag.Problematiken ligger bland annat i att det för onoterade företag saknas löpandemarknadsvärde från börsen. Dessutom är det förknippat med större svårighet att fastställadiskonteringsräntan vid användandet av en diskonteringsmodell och finna ett sannolikt måttpå risk. Problem kan även uppstå på grund av att onoterade företags värde i många fall har enstark koppling till dess ägare.Syftet med uppsatsen är att beskriva vilka delar som påverkar en värdering av ett onoterattjänsteföretag, för att därefter förklara hur ett teoretiskt förankrat värde kan fastställas. Studienomfattar bemanningsföretaget Speed Management AB och uppsatsen grundar sig på följandefrågeställningar:• Vilka delar bör beaktas vid en värdering av det onoterade företaget Speed?• Vilket värde på Speed kan slutligen uppskattas när teori förankras i empiri?Studien utgår från olika teoretiska värderingsmodeller för att påvisa arbetsgången när ettonoterat företag skall värderas. Den empiriska studien är av kvalitativ art med tre intervjuerfrån följande respondenter; en representant från Speed, en från revisionsbolaget Ernst &Young och två i en intervju med Handelsbanken. Valet av respondenter grundas på attvärderingen utförs på uppdrag av Speed där en neutral värdering efterfrågas utan att detföreligger någon försäljningssituation eller börsintroduktion. Beräkningarna i det empiriskakapitlet tillämpar teorin på Speeds räkenskaper där olika antaganden görs och Speeds egnaprognoser beaktas.Studien utgår därmed från teori om företagsvärdering, vilket appliceras på företaget Speedoch deras räkenskaper. Resultatet återanknyts till teorin och slutligen presenteras ett svar på125 000 000 kr som, i skrivande stund, kan hållas gällande som objektivt värde för Speed.

Static speed limits are the norm across the world’s roadway networks. However, advances in technology and increased applications in intelligent transportation systems (ITS) provide a mechanism for upgrading traditional speed limits into an active traffic management system. More specifically, variable speed limits (VSLs) can be used in high crash severity locations and in real-time congestion and weather events to increase traffic safety and operations. Much of the available literature on VSLs focuses upon crash prediction algorithms for VSLs, simulations, and effectiveness of real-world VSL implementations. One noticeable gap in the existing literature is related to driver compliance under varied configurations of alerting drivers of the variable speeds. An additional gap in literature is related to existence of a conceptual framework for identifying optimal corridors for potential VSL implementation. Within this thesis drivers’ willingness to comply with VSLs was investigated via focus groups and static surveys during the experimental process. Connections are made between driver speed choice and type of speed limit condition including uniform speed vi limit (USL) versus VSL, overhead mount versus side mount, presence of an explanatory message, and the numerical speed limit value. An analysis of the survey results was completed to isolate critical factors in VSL compliance. Opinions and perspectives on VSLs are derived through the focus group sessions Lastly, a case study approach is presented in which a region is chosen, and implementation metrics are analyzed on the major roadway networks using a GIS platform to create a composite ranking system for potential optimal VSL corridors. The study aims to be used as a foundation to justify use of certain types of VSLs in addition to creating a conceptual framework for VSL implementation zone identification.