Analysis of Coaches Rows Seats Distance Influence on the Passengers Comfort and Safety

Rows seats distance is a key parameter for the comfort on coaches. This distance it is also important for the passenger safety and also for example to extend the use of rearward facing CRS in a safer way. This study analyses what could be the minimum distance (based on comfort from volunteer) and how this comfort distance is affecting the passengers level of protection in R80 frontal impact with respect the minimum distance requested in current Regulations R36/R107. Volunteer testing have been performed to obtain the comfort sitting positions for coach seats geometry. Also CAE software has been used to determine minimum row seats comfort distance for a wider sample of seats geometry. In later phase, R80 sleds tests with two and four HybridIII dummies and with two types of seats (2-point and 3-point safety belts) have been performed, to asses the level of protection of the passengers in frontal impact at the current R36/R107 row seats distance and with the proposed one. This study present a recommendation for a minimum row seat distance to guarantee passengers comfort and how this distance is affecting the passengers safety in frontal impact with the injury assessment criteria of both R80 and R94 for the Hybrid-III dummy. With 3-point safety belts seats, the increment on the row seat distance is beneficial for the passengers safety, except when they are unbelted and if the design of the seat is maintained. With 2-point safety belts seats, the level of protection is similar for both distances. The R94 neck injury criteria and tibia displacement are over exceed even with the lower R80 impact speed (55 kph vs 30 kph). This study shows the status of coaches frontal impact protection levels after the 2003/20/CE Directive has been made compulsory the use of the safety belts in coaches even in the city and road travels. INTRODUCTION OBJECTIVES. Nowadays, the coaches seat spacing is established in the UNECE regulations to a minimum of 680 mm for the class II and III vehicles. The tendency in the market is to maintain this distance at minimum level in order to increased the number of available passengers seats in the vehicles. Garcia and Quintana-Domeque (2007) have shows the secular growth of the height in the population of 10 European countries during last decades. This growth in the height has conducted to a situation that during last years largest number of passenger can feel uncomfortable in the coaches travels. When the seat spacing is compared with the train seat spacing the coaches are in worst situation. It could be important to maintain a high level of satisfaction in the coaches transportation in order to not start a decreasing tendency in the use of this transport method in the population. The ergonomics study conducted have been oriented to obtain a reliable minimum seat spacing that could be evaluated as comfortable for a large sample of the population, including the tallest and shortest ones. As seat spacing is influencing the passenger safety in frontal impact, the new proposed seat spacing distance has been evaluated in terms of passenger safety. This evaluation have been performed for the two seat spacing distances, the actual and the recommended one from the ergonomics study.