Effects of new urban motorway infrastructure on road traffic accidents in the local area: a retrospective longitudinal study in Scotland

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

Interventions to reduce pedestrian road traffic injuries: A systematic review of randomized controlled trials, cluster randomized controlled trials, interrupted time-series, and controlled before-after studies

Background

Road traffic injuries are among the top ten causes of death globally, with the highest burden in low and middle-income countries, where over a third of deaths occur among pedestrians and cyclists. Several interventions to mitigate the burden among pedestrians have been widely implemented, however, the effectiveness has not been systematically examined.

Objectives

To assess the effectiveness of interventions to reduce road traffic crashes, injuries, hospitalizations and deaths among pedestrians.

Methods

We considered studies that evaluated interventions to reduce road traffic crashes, injuries, hospitalizations and/or deaths among pedestrians. We considered randomized controlled trials, interrupted time-series studies, and controlled before-after studies. We searched MEDLINE, EMBASE, Web of Science, WHO Global Health Index, Health Evidence, Transport Research International Documentation and ClinicalTrials.gov through 31 August 2020, and the reference lists of all included studies. Two reviewers independently screened titles and abstracts and full texts, extracted data and assessed the risk of bias. We summarized findings narratively with text and tables.

Results

A total of 69123 unique records were identified through the searches, with 26 of these meeting our eligibility criteria. All except two of these were conducted in high-income countries and most were from urban settings. The majority of studies observed either a clear effect favoring the intervention or an unclear effect potentially favoring the intervention and these included: changes to the road environment (19/27); changes to legislation and enforcement (12/12); and road user behavior/education combined with either changes to the road environment (3/3) or with legislation and enforcement (1/1). A small number of studies observed either a null effect or an effect favoring the control.

Conclusions

Although the highest burden of road traffic injuries exists in LMICs, very few studies have examined the effectiveness of available interventions in these settings. Studies indicate that road environment, legislation and enforcement interventions alone produce positive effects on pedestrian safety. In combination with or with road user behavior/education interventions they are particularly effective in improving pedestrian safety.

Time-dependent association between mass protests and psychological distress on social media: A text mining study during the 2019 anti-government social unrest in Hong Kong

BACKGROUND & AIMS

Social media are increasingly pivotal as the platform where activists and observers plan, promote, and respond to collective actions. To examine how mass protests influence psychological wellbeing and distress, this study analyzed their time-dependent association during the 2019 anti-government social unrest in Hong Kong.

METHODS

Consecutive day-by-day users-generated content on online forums and social network sites (SNS) from June to November 2019 was obtained. A Cantonese term-list was created to identify terms related to mass protests and psychological distress. The frequency of comments containing such terms was analyzed using time series models.

RESULTS

There were 3,572,665 social media comments in the investigation period. As hypothesized, the frequency of comments with mass protest terms was higher on days with mass protests than on days without. Frequency of comments with both mass protest- and psychological distress-terms was also higher on days with protests than days without. Time-lagged effect (responses on the following day) of protest-terms was found on online forums but not on SNS. Our results suggest a positive association between offline protest activities and online psychological reactions.

CONCLUSIONS

Social media content reveals discussions of psychological distress stemming from, or exacerbated by, social unrest. The potential mutual influences between mass protests and online reactions, as well as the functional differences between online forums and SNS in this regard are discussed. Street protests and their associated psychological distress can be readily detected on popular online forums. Mental health services should consider, and even make use of, such dynamic relationship between on- and offline activities.

Impact of law enforcement and increased traffic fines policy on road traffic fatality, injuries and offenses in Iran: Interrupted time series analysis

BACKGROUND

Road traffic law enforcement was implemented on 1st April 2011 (the first intervention) and traffic ticket fines have been increased on 1st March 2016 (the second intervention) in Iran. The aim of the current study was to evaluate the effects of the law enforcement on reduction in the incidence rate of road traffic fatality (IRRTF), the incidence rate of road traffic injuries (IRRTI) and the incidence rate of rural road traffic offenses (IRRRTO) in Iran.

METHODS

Interrupted time series analysis was conducted to evaluate the impact of law enforcement and increased traffic tickets fines. Monthly data of fatality on urban, rural and local rural roads, injuries with respect to gender and traffic offenses namely speeding, illegal overtaking and tailgating were investigated separately for the period 2009-2016.

RESULTS

Results showed a reduction in the incidence rate of total road traffic fatality (IRTRTF), the incidence rate of rural road traffic fatality (IRRRTF) and the incidence rate of urban road traffic fatality (IRURTF) by -21.44% (-39.3 to -3.59, 95% CI), -21.25% (-31.32 to -11.88, 95% CI) and -26.75% (-37.49 to -16, 95% CI) through the first intervention which resulted in 0.383, 0.255 and 0.222 decline in casualties per 100 000 population, respectively. Conversely, no reduction was found in the incidence rate of local rural road traffic fatality (IRLRRTF) and the IRRTI. Second intervention was found to only affect the IRURTF with -26.75% (-37.49 to -16, 95% CI) which led to 0.222 casualties per 100 000 population. In addition, a reduction effect was observed on the incidence rate of illegal overtaking (IRIO) and the incidence rate of speeding (IRS) with -42.8% (-57.39 to -28.22, 95% CI) and -10.54% (-21.05 to -0.03, 95% CI which implied a decrease of 415.85 and 1003.8 in monthly traffic offenses per 100 000 vehicles), respectively.

CONCLUSION

Time series analysis suggests a decline in IRTRTF, IRRRTF, and IRURTF caused by the first intervention. However, the second intervention found to be only effective in IRURTF, IRIO, and IRS with the implication that future initiatives should be focused on modifying the implementation of the traffic interventions.

Effects of transit signal priority on traffic safety: Interrupted time series analysis of Portland, Oregon, implementations

Transit signal priority (TSP) has been implemented to transit systems in many cities of the United States. In evaluating TSP systems, more attention has been given to its operational effects than to its safety effects. Existing studies assessing TSP's safety effects reported mixed results, indicating that the safety effects of TSP vary in different contexts. In this study, TSP implementations in Portland, Oregon, were assessed using interrupted time series analysis (ITSA) on month-to-month changes in number of crashes from January 1995 to December 2010. Single-group and controlled ITSA were conducted for all crashes, property-damage-only crashes, fatal and injury crashes, pedestrian-involved crashes, and bike-involved crashes. Evaluation of the post-intervention period (2003-2010) showed a reduction in all crashes on street sections with TSP (-4.5%), comparing with the counterfactual estimations based on the control group data. The reduction in property-damage-only crashes (-10.0%) contributed the most to the overall reduction. Fatal and injury crashes leveled out after TSP implementation but did not change significantly comparing with the control group. Pedestrian and bike-involved crashes were found to increase in the post-intervention period with TSP, comparing with the control group. Potential reasons to these TSP effects on traffic safety were discussed.

Geospatial and environmental analysis of road traffic accidents in the city of Resistencia, Argentina

Traffic accidents are an emerging problem in cities with high mobility and little urban planning. Evidence is lacking in Argentina regarding the relationship between the environment and accident occurrence; we therefore conducted a geospatial analysis and estimated the risk of accidents and their possible association with the characteristics of the physical environment in the city of Resistencia, Argentina occurring in 2012. Kernel density estimates were used for the spatial distribution of accidents and in parallel an observational, analytical study was carried out to analyze the factors associated with accident occurrence. The results show three critical areas (in the northwest, center and south of the city) with greater accident frequency. Environmental factors that were associated with the occurrence of accidents were the presence of street lighting (23% greater), the presence of a tree close to the road (47% greater), the presence of a traffic light (28% greater), and if the road was a major avenue (122% greater) and had curves (129% greater). This study shows the city of Resistencia to be in a situation of urban vulnerability due not only to its socioeconomic status but also to the unequal development compared to neighboring cities, a reality that fosters an unfavorable environment.

Longitudinal association between change in the neighbourhood built environment and the wellbeing of local residents in deprived areas: an observational study

BACKGROUND

Features of the urban neighbourhood influence the physical, social and mental wellbeing of residents and communities. We explored the longitudinal association between change to the neighbourhood built environment and the wellbeing of local residents in deprived areas of Glasgow, Scotland.

METHODS

A cohort of residents (n = 365; mean age 50 years; 44% male; 4.1% of the 9000 mailed surveys at baseline) responded to a postal survey in 2005 and 2013. Wellbeing was assessed with the mental (MCS-8) and physical (PCS-8) components of the SF-8 scale. We developed software to aid identification of visible changes in satellite imagery occurring over time. We then used a Geographical Information System to calculate the percentage change in the built environment occurring within an 800 m buffer of each participant's home.

RESULTS

The median change in the neighbourhood built environment was 3% (interquartile range 6%). In the whole sample, physical wellbeing declined by 1.5 units on average, and mental wellbeing increased by 0.9 units, over time. In multivariable linear regression analyses, participants living in neighbourhoods with a greater amount of change in the built environment (unit change = 1%) experienced significantly reduced physical (PCS-8: -0.13, 95% CI -0.26 to 0.00) and mental (MCS-8: -0.16, 95% CI -0.31 to - 0.02) wellbeing over time compared to those living in neighbourhoods with less change. For mental wellbeing, a significant interaction by baseline perception of financial strain indicated a larger reduction in those experiencing greater financial strain (MCS-8: -0.22, 95% CI -0.39 to - 0.06). However, this relationship was reversed in those experiencing lower financial strain, whereby living in neighbourhoods with a greater amount of change was associated with significantly improved mental wellbeing over time (MCS-8: 0.38, 95% CI 0.04 to 0.72).

CONCLUSIONS

Overall, we found some evidence that living in neighbourhoods experiencing higher levels of physical change worsened wellbeing in local residents. However, we found a stronger negative relationship in those with lower financial security and a positive relationship in those with higher financial security. This is one of few studies exploring the longitudinal relationship between the environment and health.

Effect of a new motorway on social-spatial patterning of road traffic accidents: A retrospective longitudinal natural experimental study

Background

The World Health Organisation reports that road traffic accidents (accidents) could become the seventh leading cause of death globally by 2030. Accidents often occur in spatial clusters and, generally, there are more accidents in less advantaged areas. Infrastructure changes, such as new roads, can affect the locations and magnitude of accident clusters but evidence of impact is lacking. A new 5-mile motorway extension was opened in 2011 in Glasgow, Scotland. Previous research found no impact on the number of accidents but did not consider their spatial location or socio-economic setting. We evaluated impacts on these, both locally and city-wide.

Methods

We used STATS19 data covering the period 2008 to 2014 and describing the location and details of all reported accidents involving a personal injury. Poisson-based continuous scan statistics were used to detect spatial clusters of accidents and any change in these over time. Change in the socio-economic distribution of accident cluster locations during the study period was also assessed.

Results

In each year accidents were strongly clustered, with statistically significant clusters more likely to occur in socio-economically deprived areas. There was no significant shift in the magnitude or location of accident clusters during motorway construction or following opening, either locally or city-wide. There was also no impact on the socio-economic patterning of accident cluster locations.

Conclusions

Although urban infrastructure changes occur constantly, all around the world, this is the first study to evaluate the impact of such changes on road accident clusters. Despite expectations to the contrary from both proponents and opponents of the M74 extension, we found no beneficial or adverse change in the socio-spatial distribution of accidents associated with its construction, opening or operation. Our approach and findings can help inform urban planning internationally.

Health impacts of the M74 urban motorway extension: a mixed-method natural experimental study

Background

Making travel easier can improve people’s access to opportunities, but motor transport also incurs substantial undesirable health and social impacts.

Aims

To assess how a new urban motorway affected travel and activity patterns, road accidents and well-being in local communities, and how these impacts were experienced and brought about.

Design

The Traffic and Health in Glasgow study, a mixed-method controlled before-and-after study.

Setting

Glasgow, UK.

Participants

Repeat cross-sectional survey samples of 1345 and 1343 adults, recruited in 2005 and 2013, respectively. Of these, 365 formed a longitudinal cohort, 196 took part in a quantitative substudy using accelerometers and global positioning system receivers and 30, living within 400 m of the new motorway, took part in a qualitative substudy along with 12 other informants. Complementary analyses used police STATS19 road traffic accident data (1997–2014) and Scottish Household Survey travel diaries (2009–13).

Intervention

A new 5-mile, six-lane section of the M74 motorway, opened in 2011 and running through predominantly deprived neighbourhoods in south-east Glasgow, with associated changes to the urban landscape.

Main outcome measures

Differences in self-reported travel behaviour (1-day travel record), physical activity (short International Physical Activity Questionnaire) and well-being [Short Form 8 Health Survey (SF-8) and a short version of the Warwick–Edinburgh Mental Well-being Scale], and in the incidence of road traffic accidents.

Methods

A combination of multivariable cohort, cross-sectional, repeat cross-sectional and interrupted time series regression analyses comparing residents of the ‘M74 corridor’ intervention area and two matched control areas, complemented by novel qualitative spatial methods. Graded measures of the proximity of the motorway to each participant’s home served as a further basis for controlled comparisons.

Results

Both benefits and harms were identified. Cohort participants living closer to the new motorway experienced significantly reduced mental well-being (mental component summary of the SF-8 scale) over time compared with those living further away [linear regression coefficient –3.6, 95% confidence interval (CI) –6.6 to –0.7]. In the area surrounding an existing motorway, this association was concentrated among those with chronic conditions. In repeat cross-sectional analyses, participants living closer to a new motorway junction were more likely to report using a car at follow-up than those living further away (odds ratio 3.4, 95% CI 1.1 to 10.7). We found weaker quantitative evidence of a decline in physical activity participation and no quantitative evidence of an overall change in either active travel or accidents associated with motorway exposure. Qualitative evidence suggested that, although the new motorway improved connectivity for those with dispersed social networks and access to motor vehicles, the impacts were more complex for others, some of whom found the motorway to be a cause of severance. Changes in community composition and cohesion, and perceptions of personal safety, were widely perceived as more important to local people.

Limitations

A key limitation of natural experimental studies is that the risk of residual confounding cannot be eliminated.

Conclusions

Overall, these findings highlight the potential for urban infrastructural projects of this kind to add further burdens to already disadvantaged communities, exacerbating inequalities and contributing to poorer health outcomes. The health and social impacts of such initiatives should be more fully taken into account in planning and research.

Funding

The National Institute for Health Research Public Health Research programme.