2014‐01‐31 TNSL16‐ Lecture 2 • • • • • How to measure and compare traffic safety Traffic safety problems Theories and models in traffic safety National Road Safety Programme (NRSP) Accessibility versus Mobility HOW TO MEASURE AND COMPARE ROAD SAFETY PROBLEM? Traffic Safety Measurements • Objective safety – measured with accidents rates • Perceived/subjective safety – felt by road users – e.g. The SARTRE - EU Project (Social Attitudes to Road Traffic Risk in Europe). • Nominal safety – measured in comparison to the design and operational safety standards of the products (roads, vehicles, equipment, etc) e.g. RAP (Road Assessment Program), NCAP (New Car Assessment Program). 3 1 2014‐01‐31 Main objective measurments • Traffic Risk in terms of fatalities per number of vehicles or number of kilometer driven • Personal Risk in terms of fatalities per population Risk per unit of exposure Better Enforcement and Engineering Education ITS Developing Countries Etc.. Developed Countries International comparison 2 2014‐01‐31 DIFFICULTY OF INTERNATIONAL COMPARISON OF ACCIDENTS DATA Road Traffic Accident Database Fatal Accidents Fatality Serious Injury Accidents Serious Injury victim Slight Injury Accidents Slight Injury victim Victim dies within 30 days of accident Victim given at least 7 days of medical leave Victim given at 3 days medical leave No injury Accidents No one suffers any injury CASUALTY-RELATED ACCIDENT-RELATED Sources of road accidents data • • • • • Police accident data Hospital data Insurance data Vehicle companies Special surveys Reporting rate level in a country A = number of casulaties reported to the police only B = number of casulaties reported to the police and hospitals C = number of casulaties reported to the hospital only m Missing Police A Both B Hospital Reporting level= (A+B)/(A+B+C) C Elvik and Truls (2004) 3 2014‐01‐31 Reporting rate level in a country (meta‐analysis) Elvik and Truls (2004) R El ik (H db k) Causulaty under reporting Reported and estimated casualties in ASEAN countries (2003-2004) 4 2014‐01‐31 Recommendations for European average correction factors for unreported road accidents. Bickel et al 2006 Collection of data- accident form The information sent to the national database STRADA Overview National Accident Database http://www.strada.se 5 2014‐01‐31 Accident description Traffic Safety Databases • Transportstyrelsen‐ STRADA – Informationssystem för olyckor och skador i trafiken • Trafikverket • Statistiska centralbyrån (årsbok), or SIKA • http://trafa.se/ trafik analys • OR EU Traffic Saftey Databases: – IRTAD – CARE – Eurostat (for many transport indicators) EU Road Safety Knoweldge database‐ SafetyNet (recommended to read, Weblink added to course website!) WHAT ARE THE MAIN ROAD SAFETY RISKS AND PROBLEMS? 6 2014‐01‐31 Road Safety Main Components Road Driver Vehicle Need a look under the water Obvious problems: Speeding, Alcohol and driving, usage of seatbelts and helmets, rescue services, poor road safety data, VRUs, etc. Problems need deeper analysis: Traffic legislations, enforcement, vehicle and road inspection, education, etc. Hidden problems: Traffic management system is slow or non-existent, national road safety programme, lack of know-how, etc. 7 2014‐01‐31 Shared Factors in Road Accidents 2 out of 3 accidents happen in urban roads 2 out 3 fatalities in urban roads are VRUs Fatalaties Urban roads Accidents 70% 30% Rural roads 70% 30% Pedestrian fatality Risk as function of the impact speed 8 2014‐01‐31 Alcohol Risk of crash involvement • About 20% of all road fatalities in Europe are alcohol related whereas about only 1% of all kilometres driven in Europe are driven by drivers with 0.5 g/l alcohol in their blood or more. Age and driving experience 9 2014‐01‐31 Accident peaks Age Parents Pedestrians Cyclists Mopeds Mainly knowledge and skills 28 People Aged 18‐25 Killed in Road Crashes, By Hour and Day of the Week EU 15, 2002 Car drivers fatalities by age and gender 10 2014‐01‐31 Speeding problem Why is the speed so dangerous? • A high driving speed leads to: – a high collision speed (energy) and high severity. E = 0,5*m*v2 – Longer stopping distance – Less reaction time for driver or other road users – Fuel consumption and exhaust increase – Noise increases Speed and Risk of involvement in a casualty crash 11 2014‐01‐31 How to understand the danger of high speeds? A head-on collision in 90 km/h corresponds to a free fall of 25 m and if the speeds are 110 km/tim a free fall of 43 m. How to understand the danger of high speeds? • A pedestrian hit by a car travelling 50 km/h can be compared to a free fall of 10 meters • If the speed of the car is 30 km/h it corresponds to a free fall of 3 meters The concept of “safe speed” in Sweden 36 12 2014‐01‐31 Road user behaviour in DCs‐ Examples Studies showed that: • 12 and 41 % of the drivers in selected DCs violated a red light. The corresponding figure in Sweden is 0.1-0.2%. • Road markings and signing may be less effective in some DCs than in the developed countries because of differences in driver education and behavior. • Traffic calming measures have almost the same effecteivnes in many countries. Vehicle and road safety in developing countries Road User Behaviour 13 2014‐01‐31 Road Safety Countermeasures (the 3Es) Engineering Enforcement Education Road Safety performance 5 star driving 5 star cars 5 star roads 100 Vision/Target 80 Country/City D 40-50 Best class in Performance road safety gap Country/City C Average Country/City B Country/City A 0 Time Road Safety Target Action plan and strategic direction Actual road safety performance in a country 14 2014‐01‐31 VISION ZERO : A SAFE TRAFFIC CONCEPT • History: On October 9, 1997 the "Vision Zero" was passed by a large majority in the Swedish Parliament. • Goal: “The long term goal is that no‐one shall be killed or seriously injured within the Swedish road transport system”. Philosophy behind:” – Care of human life and health is considered to be more important than anything else – Designers/Planners of traffic system are responsible for design, operation and use, and thus safety of system – Users are responsible for following the rules of use – System has to be understandable – If user fails and injuries occur, system designers and planners must take necessary steps to reduce injury – All stakeholders will share responsibility Main stages of National Road Safety Action Plan Diagnosing the road accident problem Setting up targets and visions Setting up priorities and measures Institutional coordination and responsibilities Implementation Monitoring and evaluation NRSP can tell if traffic safety development is going into the right direction in the country or not! Department Programs National Road Safety Target Sub-target Department Programs Successful NRSP needs authorities and road users to speak the same language, to understand each other, and to work together. 15 2014‐01‐31 Why is monitoring important? • Introduction of blood alcohol law in UK Source: M.J. Koomstra; Police enforcement: A European evaluation; Leidschendam, 1993 Areas with large safety potential in Sweden: • Speed: 57% of traffic volume above speed limits in 2004 (VV Konsult, 2004). • Safety belts: About 6% of car drivers do not wear safety belt (VTI, 2010) – In-depth studies show: about 34% are unbelted in fatal accidents • Drink driving: In-depth studies show: 16% of killed drivers had a BAC level over 0.2%. • ….. ”Long-term-vision” for rural roads • 70 km/h: default speed limit • 80 km/h: milled rumble strips in middle of road • 90 km/h: 2+1 roads with median milled rumble strips • 100 km/h: 2+1 roads with median barrier • 110 km/h: motorways • 120 km/h: motorways with high standard and low traffic flow 16 2014‐01‐31 Road safety is a shared responsibility between GOVERNMENT & LEGISLATIVE BODIES USERS / CITIZENS MEDIA NRSP INDUSTRY PROFESSIONALS POLICE NGOs, SPECIAL INTEREST GROUPS A shared responsibility towards: Safer people e-Safety ITS Enforcement Organisation and Managment Safer roads Safer vehicles Data collection Socio-economic factors Traffic safety development in France, 1970‐ 2009 WHO 17 2014‐01‐31 THEORIES AND MODELS IN TRAFFIC SAFETY A typical accident theory • A cleaner has a hole in his bucket. • As a result he spills water onto the floor. • A second employee is rushing and fails to see the water spot. • As a result he slips and bangs his head on the floor. Domino Theory 1932 First Scientific Approach to Accident/Prevention ‐ H.W. Heinrich 18 2014‐01‐31 Risk Homeostasis Theory (Risk Compensation) • Traffic System has their own target risk • Drivers reduce (compensate) risk with more cautious behavior if Perceived Risk > Target Risk • They change behavior towards more dangerous if Perceived Risk < Target Risk Some people are risk takers and some people are risk avoiders. Target Risk Accepted Risk Perceived Risk Why do People Engage in Risky Behavior (Accepted Risk) in Traffic 1. They don’t perceive the risk well 2. They do perceive the risk, but also perceive some benefit from taking the risk e.g. time, money, look good, personal satisfaction. etc. Risk Compensation: • The supported examples: – The average speed of people wearing seat belts was higher than those who did not – In a Munich study, half a fleet of taxicabs were equipped with anti-lock brakes (ABS), while the other half had conventional brake systems. The crash rate was the same for both types of cab, and the study concluded that drivers of ABS-equipped cabs took more risks. 19 2014‐01‐31 Perceived and Accepted Risks Sweden changed to driving on the right on 1967. It resulted in 17% less road deaths in the first year Perceived risk , Accepted risk , => Risk-taking behavior  After introducing free-market economy in Poland in late 1980s, the crash rates increased by 30 percent. Accepted risk , perceived risk  => Risk-taking behavior  Risk Compensation • The theory has generated criticism. Some critics say that the theory is not contradicted with car crash fatality rates. These rates have fallen after the introduction of engineering measures e.g. seat belt laws. Haddon’s Matrix Pre‐Crash Travelers Vehicle Road + Environment Crash Attitudes Driver Skills Alcohol Use Enforcement Education Lighting Vehicle Size Braking Vehicle Weight Post‐Crash Seat Belts Use Traveler’s Age Helmets Use Traveler’s Health First Aid Training Fuel System Fire risk Vehicle Design Road Design Weather Speed limit Road Maintenance Lighting Pedestrian facilities Roadside Hazards Fixed Objects Rescue Response Availability of Medical Services Congestion 20 2014‐01‐31 Who or what is to blame? On a dark rainy night on Saturday a young driver drove his poor‐ maintained car with friends, after party, were trying to return home. The car went out of a badly‐designed curve of a rural road and hit a tree severely directly near the road which was result in serious injuries. Although car occupants used seatbelts properly, the car was driven fast. The traffic police explained the accident due to speeding under alcohol influence. As an independent traffic safety observer, you are not entirely convinced and will use e.g. Haddon’s Matrix to categories the causes. Class Discussion The Size of Road Safety Problem = Exposure*Risk*Consequence Accident Risk (A/E) Exposure (E) Injury Risk (I/A) “Consequences” (I) = E*A/E*I/A Source: Rumar (1999) The traffic safety situation - Annual number of killed car drivers in different age groups in Sweden 1992 Source: Nilsson (1999) 21 2014‐01‐31 Risk description using different exposure units, person kilometres or hours in traffic, for road users, Sweden 1992 Source: Nilsson (1999) Mobility & Accessibility • Mobility refers to the movement of people and goods between different sites – If a transport mode could move people and goods very fast then that mode provides very high mobility • Accessibility refers to the ability to reach desired destinations (goods, services, activities, etc) – If a transport mode provides connection to large number of residences, commercial places and industrial places then it provides very high accessibility Road Functions Mobility Accessibility 22 2014‐01‐31 Mobility & Accessibility Expressways Multilane Highways Mobility State Highways Major District Roads Other District Roads Village Roads Access Mobility & Accessibility Mode choice Variables determine mode choice • Private Transport: Cars • Collective Transport: • • • • • • • • • – – – – – Bus Light Rail Rapid Transit Taxi CarSharing • Non Motorized Modes – Walking – Biking Cost Availability and Frequency Waiting Time “Value‐of‐Time”‐ average Travel time Comfort Safety Security Accessibility to service Mobility Example (1) ‐ The ICA model Zone 3 Zone 2 Zone 1 Hemköp * * * Zone 4 No ICA * * Zone 5 * How can I get better accessibility to ICA/IKEA/…? • To stay in zones closer to one • ICA could build one near my place • The transport system could improve accessibility • …. 23 2014‐01‐31 ICA Model Accessibility from Zone i to ICA Ai = ∑ # of ICA in Zone j j=1,5 t tij If there is no ICA in Zone 4, the mobility (fast connection) between Zone 3 and Zone 4 is not important (with respect to the trip purpose in reaching ICA). Example (2) • If a school experienced traffic or parking congestion problems. – Mobility‐based analysis would conclude that roads and parking facilities could be expanded, or that students could travel by bus, rather than drive alone. – Accessibility‐based analysis would look to the location of the school and residential areas in where the distance that children must travel to school is short enough to allow more walking and cycling. 24