The growing population and motorization generate more movements. In many cities, the increase of population and motorization is much greater than the development of the capacity of the transportation network. For unprotected road users, the risk of getting in a traffic accident increases and the risk of being more severely injured in an accident. In March 2020, a pandemic was declared because of a Coronavirus. More people started to work/study from home to prevent the virus from spreading by avoiding unnecessary trips, gatherings, and crowded areas. Therefore, travel behaviours have shifted during the pandemic compared to previous years. This project aims to get knowledge of how mobility and traffic accidents are affected by significant shifts of travel flow, predict the effect of traffic accidents based on mobility, and evaluate the risk of travelling on a particular road segment. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

This study is the first randomised controlled trial (RCT) of the safety effect of high-visibility bicycle clothing. The hypothesis was that the number of cyclist accidents can be reduced by increasing the visibility of the cyclists. The study design was an RCT with 6793 volunteer cyclists – 3402 test cyclists (with a yellow jacket) and 3391 control cyclists (without the jacket). The safety effect of the jacket was analysed by comparing the number of self-reported accidents for the two groups. The accident rate (AR) (accidents per person month) for personal injury accidents (PIAs) for the test group was 47% lower than that of the control group. For accidents involving cyclists and motor vehicles, it was 55% lower. The study was non-blinded, and the number of reported single accidents was significantly lower in the test group than in the control group. This is likely a result of a response bias, since the bicycle jacket was not expected to affect the number of single accidents. To compensate for this bias, a separate analysis was carried out. This analysis reduced the effect of the jacket from 47% to 38%.

Ambulanssjukvården är idag en högteknologisk del av den svenska vårdkedjan där patienten ska förväntas möta samma vårdkvalité som i den övriga vården. Ambulansen är utformad till ett vårdrum där patienten ska kunna vårdas, behandlas och transporteras till sjukhus på ett säkert sätt. Prioritet-1 transport innebär att ambulansen med siren och/eller blåljus påkallar fri väg för att snabbt kunna ta sig till skadeplats och patient, eller snabbt kunna transportera patient till sjukhus. Dessa transporter innebär att ambulansen framförs i hastigheter över rådande hastighetsbestämmelser, och utgör en trafiksäkerhetsrisk för både omgivning, personal i ambulansen och patienten. Tidigare forskning har visat att majoriteten av ambulansrelaterade olyckor uppkommer under prioritet-1 transporter. Samtidigt som det innebär en flerfaldigt förhöjd risk för skador med dödlig utgång för personalen i vårdutrymmet vid dessa olyckor jämfört med personal i förarhytten. Detta förklaras av ambulansens design och tekniska utformning samt låg grad av bältesanvändning hos vårdande ambulanspersonal. Ambulanspersonalen har beskrivit att de vid omhändertagandet av den kritiskt sjuke patienten behöver vara obältade under transporten för att utföra avancerad och livsuppehållande behandling under transport. Att transportera patienter är en av de huvudsakliga uppgifterna i dagens ambulanssjukvård, och i ambulanssjuksköterskans kompetensbeskrivning beskrivs att denne ska kunna transportera patienten på ett patient- och trafiksäkert sätt. Studiens syfte var att beskriva sjuksköterskors bedömning av trafiksäkerheten i ambulansens vårdutrymme under prioritet-1 transport till sjukhus. En webenkät utformades för att undersöka sjuksköterskors bedömning av tre identifierade trafiksäkerhetsrisker i vårdutrymmet, den obältade vårdaren, den obältade patienten samt förekomsten av lösa föremål. Resultatet visade en låg bältesanvändning för vårdande sjuksköterska under transport, en hög bältesanvändning för patienten samt en hög förekomst av lösa föremål i vårdutrymmet. Sjuksköterskans utbildning påverkade inte bältesanvändningen för vårdaren, bältesanvändningen för patienten eller förekomsten av lösa föremål. Dock visade resultatet att specialistsjuksköterskorna inom ambulanssjukvård, bedömde trafiksäkerhetsrisken högre för patienten vid de tillfällen då vårdaren var obältad, än de grundutbildade sjuksköterskorna. Vidare ansåg flera av respondenterna att tidsintervallet då hen var obältad och förekomst av lösa föremål utgjorde en högre risk för vårdande sjuksköterska än för patienten. Det var författarnas slutsats att prioritet-1 transporter med ambulans framförs i höga hastigheter, detta med ökad skade-och mortalitetsrisk för ambulanspersonal och patient vid en eventuell kollision. En markant lägre bältesanvändning hos ambulanspersonalen i vårdutrymmet jämfört med nationell data av civila bilister i Sverige, samt av ambulanspersonalen upplevd dålig fordonsdesign med lösa föremål som följd ökar skaderisken ytterligare. Ambulanspersonalen saknar kunskap kring de risker det innebär att färdas obältad i ett fordon, samt kunskap kring de skador lösa föremål kan åstadkomma vid eventuell skadehändelse med involverad ambulans. Vårdmiljön i ambulansen har stor förbättringspotential, där design och utformning kan minska behovet av vårdarens rörlighet och förekomsten av lösa föremål. Kunskap kring trafiksäkerhet och dess betydelse för patient och vårdare behöver ökas hos den operativa ambulanspersonalen. Nyckelord: prehospital, trafiksäkerhet, utryckningskörning, bältesanvändning, lösa föremål / Ambulance care is today an advanced medical instance of the Swedish care system, where patients can expect to meet the same quality of care as in any other care institution. The ambulance is designed to be used as a room for care where the patient can be safely treated and transported to hospitals in a safe way. Priority-1 transport means that the ambulance with the siren and/or lights, demands free access on the road, to quickly get to the patient, or to quickly transport the patient to the hospital. These transports mean that the ambulance drives at speeds that exceeds speed limits, and poses a road safety hazard to both the environment, ambulance staff and the patient. Previous research has shown that the majority of ambulance-related accidents occur under priority-1 transports. At the same time as it involves a multiple increased risk of fatal injury for the personnel in the care space. This is explained by the ambulance's technical design and low proportion of belt use in ambulance staff. Ambulance staff have described that when handling the severely ill patient, they need to be unbelted during transportation to perform advanced and life-saving treatment during transportation. The patient transport to, or between hospitals is one of the main tasks in today's ambulance care, and in the ambulance nurse's competence description it is described that the ambulance nurse should be capable of transporting the patient in a patient-and road safe way.   The purpose of the study was to describe the nurse's assessment of road safety in the ambulance care area, under priority-1 transport to hospitals.   A web survey was designed to investigate the nurse's assessment of three identified road safety risks in the care area, the unbelted care provider, the unbelted patient and the presence of loose objects.   The result showed a low belt usage for the staff during transport, a high belt use for the patient and a high incidence of loose items in the care space. The nurses level of education did not affect the use of seat belts for the nurses, seat belt use or the occurrence of loose objects. However, the result of the fact that the ambulance nurse compared with the undergraduate nurse assessed the road safety risk higher for the patient on occasions when the caretaker was unbelted. It was significantly more common that the nurse considered the time interval when he or she was unbelted as a risk for him/ herself, and the loose objects occur to be posed a higher risk to the caregiver than to the patient. It was the authors' conclusion that priority 1 transports with ambulances are performed at high speeds, whit increased injury and mortality risk for ambulance staff and patient in a possible collision. A significantly lower seat belt use of ambulance staff in the care space compared to national data of civilian drivers in Sweden, as well as the ambulance staff's experience of poor vehicle design with loose items as a consequence, increases the risk of injury further. The care space in the ambulance has great potential for design improvments which can reduce ambulance nurses need of mobility and the presence of loose objects. Knowledge of traffic safety and its importance for patients and care givers, needs to be increased in the operational ambulance personnel.   Keywords: prehospital, traffic safety, emergency driving, seat belt use, loose objects

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No description available.

With the growing number of vehicles on the road, improving traffic safety and efficiency has become a major challenge. One of the promising solutions is the implementation of Intelligent Transportation Systems (ITS), which utilizes communication technologies to facilitate real-time information sharing between vehicles and infrastructure. This research aims to contribute to the field of Intelligent Transportation Systems (ITS) improving traffic safety and efficiency achieving the Vision Zero goal. In this thesis, we focus on the performance analysis of two communication protocols used for two signal dissemination techniques for IVI (infrastructure-vehicle-information communication). Periodic, which sends signals at fixed intervals, and On-demand which sends signals upon request from road users. The results of our experiments showed that there are trade-offs between the periodic and on-demand approaches in V2I communications. The on-demand approach performs better in terms of PER (Packet error ratio), but it results in higher latency, even with low congestion. On the other hand, the periodic approach exhibits higher PDR (Packet delivery ratio) but suffers from inefficiencies due to the transmission of redundant messages resulting in higher PER. Our findings have implications for the scalability of V2I communications and can be translatable to other access technologies used in ITS.

Safety in transportation systems is of paramount concern to society; many improvements have been made in recent decades and yet thousands of fatalities still occur annually. Work zones in particular are areas with increased safety risks in transit networks. Advances in electronics have now allowed engineers to merge powerful computing and communication technologies with modern automotive and vehicular technology, known as connected vehicle. Connected vehicle will allow vehicles to exchange data wirelessly with each other and infrastructure to improve safety, mobility and sustainability. This thesis presents a paper that focuses on evaluating the impact of connected vehicle on work zone traffic safety. A dynamic route guidance system based on decaying average-travel-time and shortest path routing was developed and tested in a microscopic traffic simulation environment to avoid routes with work zones. To account for the unpredictable behaviour and psychology of driver’s response to information, three behaviour models, in the form of multinomial distributions, are proposed and studied in this research. The surrogate safety measure improved Time to Collision was used to gauge network safety at various market penetrations of connected vehicles. Results show that higher market penetrations of connected vehicles decrease network safety due to increased average travel distance, while the safest conditions, 5%-10% reduction in critical Time to Collision events, were observed at market penetrations of 20%-40% connected vehicle, with network safety strongly influenced by behaviour model. / Thesis / Master of Applied Science (MASc)

Current literature predicts that climate change may increase both the occurrence and severity of heavy rainfall events and winter precipitation in the Northeast United States. A potential increase in intense precipitation events related to climate change would theoretically also cause an increase in weather-related delays, increase in overall traffic disruptions, a substantive shift in travel behavior, and presumably a negative effect on safety and maintenance operations of highways. This current research study examines the existing impacts from both an operational and behavioral perspective of how weather events currently impact overall safety along routes in Massachusetts. A secondary objective of the research effort is to evaluate the extent to which this information is captured on the crash report form for subsequent use in safety analyses. Utilizing data from Massachusetts Department of Transportation, National Climatic Data Center (NCDC) and the University of Massachusetts Data Warehouse, crash statistics were examined during varied levels of weather events and compared with non-weather conditions. In addition, crash report forms were analyzed in comparison to NCDC weather data to determine the correlation between of the weather specific fields of the reports and to help determine if crashes were weather-related. The results from the investigation show how the character of precipitation events impact traffic safety including both occurrence and intensity levels and in conjunction with existing weather predictions the relationships developed in this study are useful in evaluating how changes in extreme precipitation events projected for the Northeast may impact drivers’ safety in the future.

Incorporating safety into the transportation planning stage, which is often termed as transportation safety planning (TSP), relies on the vital interplay between zone characteristics and zonal traffic crashes. Although a few safety studies had made some effort towards integrating safety and planning, several unresolved problems and a complete framework of TSP are still absent in the literature. This research aims at examining the suitability of the current traffic-related zoning planning process in a new suggested planning method which incorporates safety measures. In order to accomplish this broader research goal, the study defined its research objectives in the following directions towards establishing a framework of TSP- i) exploring the existing key determinants in traditional transportation planning (e.g., trip generation/distribution data, land use types, demographics, etc.) in order to develop an effective and efficient TSP framework, ii) investigation of the Modifiable Aerial Unit Problem (MAUP) in the context of macro-level crash modeling to investigate the effect of the zone's size and boundary, iii) understanding neighborhood influence of the crashes at or near zonal boundaries, and iv) development of crash-specific safety measure in the four-step transportation planning process. This research was conducted using spatial data from the counties of West Central Florida. Analysis of different crash data per spatial unit was performed using nonparametric approaches (e.g., data mining and random forest), classical statistical methods (e.g., negative binomial models), and Bayesian statistical techniques. In addition, a comprehensive Geographic Information System (GIS) based application tools were utilized for spatial data analysis and representation. Exploring the significant variables related to specific types of crashes is vital in the planning stages of a transportation network. This study identified and examined important variables associated with total crashes and severe crashes per traffic analysis zone (TAZ) by applying nonparametric statistical techniques using different trip related variables and road-traffic related factors. Since a macro-level analysis, by definition, will necessarily involve aggregating crashes per spatial unit, a spatial dependence or autocorrelation may arise if a particular variable of a geographic region is affected by the same variable of the neighboring regions. So far, few safety studies were performed to examine crashes at TAZs and none of them explicitly considered spatial effect of crashes occurring in them. In order to understand the clear picture of spatial autocorrelation of crashes, this study investigated the effect of spatial autocorrelation in modeling pedestrian and bicycle crashes in TAZs. Additionally, this study examined pedestrian crashes at Environmental Justice (EJ) TAZs which were identified in compliance with the various ongoing practices undertaken by Metropolitan Planning Organizations (MPOs) and previous research. Minority population and the low-income group are two important criteria based on which EJ areas are being identified. These unique areal characteristics have been of particular interest to the traffic safety analysts in order to investigate the contributing factors of pedestrian crashes in these deprived areas. Pedestrian and bicycle crashes were estimated as a function of variables related to roadway characteristics, and various demographic and socio-economic factors. It was found that significant differences are present between the predictor sets for pedestrian and bicycle crashes. In all cases the models with spatial correlation performed better than the models that did not account for spatial correlation among TAZs. This finding implied that spatial correlation should be considered while modeling pedestrian and bicycle crashes at the aggregate or macro-level. Also, the significance of spatial autocorrelation was later found in the total and severe crash analyses and accounted for in their respective modeling techniques. Since the study found affirmative evidence about the inclusion of spatial autocorrelation in the safety performance functions, this research considered identifying appropriate spatial entity based on which TSP framework would be developed. A wide array of spatial units has been explored in macro-level crash modeling in previous safety research. With the advancement of GIS, safety analysts are able to analyze crashes for various geographical units. However, a clear guideline on which geographic entity should a modeler choose is not present so far. This preference of spatial unit can vary with the dependent variable of the model. Or, for a specific dependent variable, models may be invariant to multiple spatial units by producing a similar goodness-of-fits. This problem is closely related to the Modifiable Areal Unit Problem which is a common issue in spatial data analysis. The study investigated three different crash (total, severe, and pedestrian) models developed for TAZs, block groups (BGs) and census tracts (CTs) using various roadway characteristics and census variables (e.g., land use, socio-economic, etc.); and compared them based on multiple goodness-of-fit measures. Based on MAD and MSPE it was evident that the total, severe and pedestrian crash models for TAZs and BGs had similar fits, and better than the ones developed for CTs. This indicated that the total, severe and pedestrian crash models are being affected by the size of the spatial units rather than their zoning configurations. So far, TAZs have been the base spatial units of analyses for developing travel demand models. Metropolitan planning organizations widely use TAZs in developing their long range transportation plans (LRTPs). Therefore, considering the practical application it was concluded that as a geographical unit, TAZs had a relative ascendancy over block group and census tract. Once TAZs were selected as the base spatial unit of the TSP framework, careful inspections on the TAZ delineations were performed. Traffic analysis zones are often delineated by the existing street network. This may result in considerable number of crashes on or near zonal boundaries. While the traditional macro-level crash modeling approach assigns zonal attributes to all crashes that occur within the zonal boundary, this research acknowledged the inaccuracy resulting from relating crashes on or near the boundary of the zone to merely the attributes of that zone. A novel approach was proposed to account for the spatial influence of the neighboring zones on crashes which specifically occur on or near the zonal boundaries. Predictive model for pedestrian crashes per zone were developed using a hierarchical Bayesian framework and utilized separate predictor sets for boundary and interior (non-boundary) crashes. It was found that these models (that account for boundary and interior crashes separately) had better goodness-of-fit measures compared to the models which had no specific consideration for crashes located at/near the zone boundaries. Additionally, the models were able to capture some unique predictors associated explicitly with interior and boundary-related crashes. For example, the variables- 'total roadway length with 35mph posted speed limit' and 'long term parking cost' were statistically not significantly different from zero in the interior crash model but they were significantly different from zero at the 95% level in the boundary crash model. Although an adjacent traffic analysis zones (a single layer) were defined for pedestrian crashes and boundary pedestrian crashes were modeled based on the characteristic factors of these adjacent zones, this was not considered reasonable for bicycle-related crashes as the average roaming area of bicyclists are usually greater than that of pedestrians. For smaller TAZs sometimes it is possible for a bicyclist to cross the entire TAZ. To account for this greater area of coverage, boundary bicycle crashes were modeled based on two layers of adjacent zones. As observed from the goodness-of-fit measures, performances of model considering single layer variables and model considering two layer variables were superior from the models that did not consider layering at all; but these models were comparable. Motor vehicle crashes (total and severe crashes) were classified as 'on-system' and 'off-system' crashes and two sub-models were fitted in order to calibrate the safety performance function for these crashes. On-system and off-system roads refer to two different roadway hierarchies. On-system or state maintained roads typically possess higher speed limit and carries traffic from distant TAZs. Off-system roads are, however, mostly local roads with relatively low speed limits. Due to these distinct characteristics, on-system crashes were modeled with only population and total employment variables of a zone in addition to the roadway and traffic variables; and all other zonal variables were disregarded. For off-system crashes, on contrary, all zonal variables was considered. It was evident by comparing this on- and off-system sub-model-framework to the other candidate models that it provided superior goodness-of-fit for both total and severe crashes. Based on the safety performance functions developed for pedestrian, bicycle, total and severe crashes, the study proposed a novel and complete framework for assessing safety (of these crash types) simultaneously in parallel with the four-step transportation planning process with no need of any additional data requirements from the practitioners' side.

Crashes categorized as running red light or left turning are most likely to occur at signalized intersections and resulted in substantial severe injuries and property damages. This dissertation mainly focused on these two types of vehicle crashes and the research methodology involved several perspectives. To examine the overall characteristics of red-light running and left-turning crashes, firstly, this study applied 1999-2001 Florida traffic crash data to investigate the accident propensity of three aspects of risk factors related to traffic environments, driver characteristics, and vehicle types. A quasi-induced exposure concept and statistical techniques including classification tree model and multiple logistic regression were used to perform this analysis. Secondly, the UCF driving simulator was applied to test the effect of a proposed new pavement marking countermeasure which purpose is to reduce the red-light running rate at signalized intersections. The simulation experiment results showed that the total red-light running rate with marking is significantly lower than that without marking. Moreover, deceleration rate of stopping drivers with marking for the higher speed limit are significantly less than those without marking. These findings are encouraging and suggesting that the pavement marking may result in safety enhancement as far as right-angle and rear-end traffic crashes at signalized intersections. Thirdly, geometric models to compute sight distances of unprotected left-turns were developed for different signalized intersection configurations including a straight approach leading to a straight one, a straight approach leading to a curved one, and a curved approach leading to a curved one. The models and related analyses can be used to layout intersection design or evaluate the sight distance problem of an existing intersection configuration to ensure safe left-turn maneuvers by drivers.