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The Social Cost of PRT Malfunction

Since JPods are suspended from the guideway, a question that often comes up is, what happens if the JPod breaks down. The first thing you might imagine, is climbing down the ladder on a fire truck while onlookers watch. Thats not what really happens, but first lets discuss what happens when other modes of transportation break down.

An Automobile: Imagine your car breaks down in the middle of a busy street. There isn't enough room to get it off the road, so instead the two lane road has been reduced to one. A traffic jam develops on the street, making hundreds of other motorist late for thier scheduled activities. You can't abondon your car because it is against the law, so you must wait beside it for a tow truck to move it. Luckily your AAA membership gives you a free tow, but you still had to wait 45 minutes for the tow truck to arrive. Once the tow truck moves your car, you still don't have a good way to get to and from your desination. Lets assume the 100 other motorists added 3 minutes to thier travel, while you added 2 hours to your day. Total time cost: 7 hours (120 min + 3x100 min)

A Bus: A city bus isn't too bad. If they are frequent enough, you can catch the next one in 15-20 minutes. If your Transportation Authority is on top of it, they might send an empty bus to come and continue the route. Lets assume 39 others were on the bus with you. Lets again assume a 2 lane road as we did in the automobile senario. The bus also causes a traffic jam, adding 3 minutes to 100 motorists commute time. Total time cost: 15 hours (40x15 min 3x100 min)

A Train: A train might be carrying 200+ passengers. If it breaks down and there is only one line going in both directions, it could cause a ripple effect throught the whole system, delaying all subsequent trains. It might take an hour to get the train moving again. Meanwhile it delayed the next 3 trains by 45 mins, 30 mins, and 15 mins. Total time cost:  500 hours (200x60 min + 200x45 min + 200x30 min + 200x15 min)

A JPod: If a JPod stops moving on the guideway, there are a number of back-up and contingency systems that start to operate. If it is not a motor issue, the JPod has enough power in the onboard battery to get you to the next station, at which time you would board a JPod waiting for you at the station. Lets assume for the case of this senario that it is a motor issue and the JPod doesn't move. First the stopped JPod, sends a signal to the Vehicle Control System which warns the other JPods of the blocked track. This re-routes the other JPods to the next fastest route. Lets assume there are the same amount of people using the JPods system as the train. Of those 800 passengers, 200 of them might be affected by the stationary JPod. By taking an alternate route, the affected JPods add an average of 2 minutes to their travel time. Meanwhile an emergency pusher-puller bogie is dispatched to the stationary JPod. The emergency bogie can push or pull the JPod to the next station. Wait time for the emergency bogie is 15 minutes. Once at the next available station you board a waiting JPod. Total time cost: 6.9 hours (15 min + 200x2 min) 

Often times we only think of the personal cost of time when our mode of transportation breaks down. In the senario above, the automobile malfunction is the most costly in terms of time for the individual. If we take a global perspective and consider everyone utilizing each tranportation network, we find that the modes considered most efficent, are the most costly in terms of time if they don't work. JPods get the benefits of having low social and personal time cost if they break down, while still getting to service large amounts of passengers simlar to a train.

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