We have now had two days of the FSGP – the track-race portion of the American Solar Challenge. Lap counts so far are shown in the chart below. The chart is in the colours of the Kansas flag, with green bars representing single-occupant vehicles (SOV). Stars mark the five teams that have already qualified for the coming road race (see also my illustrated list of teams). The Gato del Sol VI from Kentucky is in the lead, having done even better than I expected.
To follow the multi-occupant vehicles (MOV), it is only necessary to look at the brown bars in the chart above. Technically, the FSGP regulations give the score for MOV cars as S = (D / E) × C × T, where S is the total score, D is the Total Person-Mile Distance, E is the Total External Energy usage of the solar car, C is the Completion Factor, and T is the Target Speed Derate.
The chart above (click to zoom) visualises these MOV scores on a logarithmic axis, with six coloured bars being components of the score, and the seventh coloured bar S being the product (and therefore the sum of the logarithms) of those components. The six components are:
- d, the total miles driven
- d′, the total miles driven with penalties
- p, the average number of persons in the car (and so D = d × p)
- E, the total external energy usage (as in the regulations)
- T, the target speed derate, which penalises cars slower than 30 mph (as in the regulations)
- h, a grey bar (the same for every team) showing the highest driving distance of any MOV entry (and so C = d′ / h)
This version of the formula, S = d × d′ × p × (1/E) × T × (1/h), makes it clear that the speed of the car appears three times, and hence dominates all the other factors. Consequently, we really only need to count laps. Another consequence is that teams in the MOV (Cruiser) class would, in many cases, actually be better off not carrying passengers.
Scientific Gems 