World Solar Challenge Cruiser Scores Revisited

Above (click to zoom) are the World Solar Challenge 2019 Cruiser practicality scores. Image credits are as per my illustrated list of teams. That list also includes practicality score guesses – but I did a poor job of guessing (a correlation of only 0.75 with actual scores). That reflects the change in practicality scoring this year, with several of the less subjective elemehts removed. Four cars this year had higher practicality scores than when they last appeared:

  • Minnesota (team 35) from 57 to 76.3 (a surprisingly large change, although it is a very nice car)
  • Flinders (team 14) from 46.7 to 63.7 (this team did make many improvements)
  • HK IVE (team 25) from 45.2 to 63.4 (this team did make many improvements)
  • Lodz (team 45) from 79.1 to 82.4 (a surprisingly small change, given the extensive improvements)

Two cars had lower practicality scores than when they last appeared:

  • Bochum (team 11; they fielded this car in 2015) from 80.5 to 75.1 (a surprising score, given the fantastic interior)
  • Sunswift (team 75) from 80 to 69.5 (also surprising, although they did take the rear seats out)

The chart above (click to zoom) shows final Cruiser scores (including practicality) in the style of my previous chart. The score is calculated as a product S = D × H × (1 / E) × P × 0.99l. The chart shows the components of the score on a logarithmic scale, so that multiplying and dividing score components corresponds to adding and subtracting bars. For each team, there are 6 bars (the 6th bar, in a darker colour, is the total score):

  1. The distance travelled in km (D). Teams given credit for completing the entire course score ahead of others.
  2. The weighted average number of humans (H) in the car (so that the product D×H is the number of person-kilometres). A small tick mark above the bar shows the number of seats in the car, which is the maximum possible value of H for that team.
  3. The nominal external energy usage (E) in kWh (initial battery capacity, plus metered charging along the way). This bar is negative, because we are dividing by E.
  4. The practicality score divided by 100. This bar is negative, since the highest possible value is 1.0 (this means that longer bars mean lower values). A tick mark under the column shows the lowest practicality score across all six teams, which is 0.534.
  5. The lateness factor (0.99l), where l is the number of minutes of late arrival, plus the number of demerit points.
  6. The total score (S). The score itself is shown over the bar. It can be seen by inspection that this bar is the sum of the others.

Well done, Eindhoven!