2019 World Solar Challenge: the route

Following on from my route map above for the World Solar Challenge (click to zoom), here are some personal route notes (revised from 2015 and 2017). The WSC has confirmed that the control stops are as indicated.

The graph below (click to zoom) shows approximate altitudes (taken from the Stanford 2013 elevation profile for this version of the graph). The highest point on the route (about 730 m) is 20 km north of Alice Springs, although the steepest hill (Hayes Creek Hill, summit 203 m) is about 170 km from Darwin.

Darwin – Start


Solar Team Eindhoven’s Stella starts the race in 2013 (photo: WSC)

The city of Darwin marks the start of the race.

Katherine – 322 km – Control Stop 1


En route to Katherine in 2011 (photo: UC Berkeley Solar Vehicle Team)

The town of Katherine (on the Katherine River) is a gateway to Nitmiluk National Park. It also serves the nearby Royal Australian Air Force base. The average maximum October temperature is 37.7°C.

Daly Waters – 588 km – Control Stop 2


The famous Daly Waters pub (photo: Lakeyboy)

Daly Waters is a small town with a famous pub. The Eindhoven team left a shirt there in 2015.

Dunmarra – 633 km


University of Toronto’s Blue Sky Solar team leaves the Dunmarra control stop in 2013 (photo: Blue Sky Solar)

Dunmarra once served the Overland Telegraph Line. Today it is little more than a roadhouse, motel, and caravan park. In previous races, this was a control stop.

Tennant Creek – 987 km – Control Stop 3 / End of Cruiser Stage 1


Tennant Creek (photo: Tourism NT)

Tennant Creek (population about 3,500) is a small town serving nearby mines, cattle stations, and tourist attractions. Shopping can be done at Tennant Creek IGA.

For 2019, Tennant Creek marks the end of Cruiser Stage 1. Cruisers must arrive between 14:00 and 17:00 on Monday (with penalties for arriving after 14:00). Cruiser teams will spend the night, and have the option of metered recharging between sunset and 23:00.

Karlu Karlu / Devils Marbles Conservation Reserve


Nuon Solar Team’s Nuna7 drives by the Devils Marbles in 2013 (photo: Jorrit Lousberg)

The 1,802 hectare Karlu Karlu / Devils Marbles Conservation Reserve lies along both sides of the Stuart Highway about 100 km south of Tennant Creek. It is home to a variety of reptiles and birds, including the fairy martin (Petrochelidon ariel) and the sand goanna (Varanus gouldii). Race participants, of course, don’t have time to look (unless, by chance, this is where they stop for the night).

Barrow Creek – 1,210 km – Control Stop 4


Barrow Creek Roadhouse and surrounds (photo: Adrian Kitchingman)

Barrow Creek once served the Overland Telegraph Line and nearby graziers, but is now nothing but a roadhouse. The Telegraph Station is preserved as a historical site.

Ti Tree – 1,300 km


Nuon Solar Team’s Nuna6 drives by a fire between Tennant Creek and Alice Springs in 2011 (photo: Hans Peter van Velthoven)

Ti Tree is a small settlement north of Alice Springs. Much of the local area is owned by the Anmatyerre people. In previous races, this was a control stop.

Alice Springs – 1,493 km – Control Stop 5


Alice Springs (photo: Ben Tillman)

Alice Springs is roughly the half-way point of the race.

Kulgera – 1,766 km – Control Stop 6


Sunset near Kulgera (photo: “dannebrog”)

Kulgera is a tiny settlement 20 km from the NT / SA Border. The “pub” is Kulgera’s main feature.

NT / SA Border – 1,786 km


Entering South Australia (photo: Phil Whitehouse)

The sign at the Northern Territory / South Australia border shows Sturt’s Desert Pea (Swainsona formosa), the floral emblem of the state of South Australia.

Marla – 1,945 km


Road train at Marla (photo: Ed Dunens)

Marla (population 100) has a health centre, a roadhouse/motel/supermarket complex, a police station, and a small car repair workshop. The name of the town may be a reference to the mala (Lagorchestes hirsutus) or to an Aboriginal word for “kangaroo.”

Coober Pedy – 2,178 km – Control Stop 7 / End of Cruiser Stage 2


Coober Pedy (photo: “Lodo27”)

The town of Coober Pedy is a major centre for opal mining. Because of the intense desert heat, many residents live underground.

For 2019, Coober Pedy marks the end of Cruiser Stage 2. Cruisers must arrive between 16:30 and 17:00 on Wednesday (with penalties for arriving after 16:30). Cruiser teams will spend the night, and have the option of metered recharging between sunset and 23:00.

Glendambo – 2,432 km – Control Stop 8


The Belgian team’s Indupol One leaves Glendambo control stop in 2013 (photo: Punch Powertrain Solar Team / Geert Vanden Wijngaert)

Glendambo is another small outback settlement.

Port Augusta – 2,720 km – Control Stop 9

At Port Augusta, the highway reaches the Spencer Gulf. From this point, traffic becomes much heavier, which makes life more difficult for the drivers in the race.

Adelaide – Finish


Adelaide makes quite a contrast to that lengthy stretch of desert (photo: “Orderinchaos”)

Adelaide, the “City of Churches,” is the end of the race. The official finish line marks 3,022 km from Darwin.

Cruisers must arrive between 11:30 and 14:00 on Friday (with penalties for arriving after 11:30).


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Personality and Gender

The so-called “Big Five” personality traits are often misunderstood. They all have catchy names, expressed by the acronym CANOE (or OCEAN), but in fact all they are is a summary of answers to certain kinds of personality questions:

  • Conscientiousness: I pay attention to details; I follow a schedule; …
  • Agreeableness: I am interested in people; I feel the emotions of others; …
  • Neuroticism: I get upset easily; I worry about things; …
  • Openness to experience: I am full of ideas; I am interested in abstractions; …
  • Extraversion: I am the life of the party; I start conversations; … (this last one is also measured by the MBTI test)

These tests work in multiple cultures. In this article, I am using data from the Dutch version of the test, the “Vijf PersoonlijkheidsFactoren Test” developed by Elshout and Akkerman. Specifically, I am using data from 8,954 psychology freshmen at the University of Amsterdam during 1982–2007 (Smits, I.A.M., Dolan, C.V., Vorst, H.C., Wicherts, J.M. and Timmerman, M.E., 2013. Data from ‘Cohort Differences in Big Five Personality Factors Over a Period of 25 Years’. Journal of Open Psychology Data, 1(1), p.e2). In my analysis, I have compensated for missing data and for the fact that the sample was 69% female.

The Dutch test consists of 70 items, in 5 groups of 14. The following tree diagram (click to zoom) is the result of UPGMA hierarchical clustering on pairwise correlations between all 70 items. It can be seen that they naturally cluster into 5 groups corresponding almost perfectly to the “Big Five” personality traits – the exception being item A11, which fits extraversion slightly better (r = 0.420) than its own cluster of agreeableness (r = 0.406). This lends support to the idea that the test is measuring five independent things, and that these five things are real.

On tests like this, women consistently score, on average, a little higher than men in conscientiousness, agreeableness, neuroticism, and extraversion (and in this dataset, on average, a little lower in openness to experience). Mean values for conscientiousness in this dataset (on a scale of 14 to 98) were 60.3 for women and 56.1 for men (a difference of 4.2). For agreeableness, they were 70.6 for women and 67.6 for men (a difference of 3.0). There are also small age effects for conscientiousness, agreeableness, and openness to experience (over the 18–25 age range), which I have ignored.

The chart below (click to zoom) shows distributions of conscientiousness and agreeableness among men and women, and the relative frequency of different score ranges (compensating for the fact that the sample was 69% female). Thus, based on this data, a random sample of people with both scores in the range 81 to 90 would be 74% female. With both scores in the range 41 to 50, the sample would be 72% male. This reflects a simple mathematical truth – small differences in group means can produce substantial differences at the tails of the distribution.


American Solar Challenge 2018: The run to Burns

I recently got my hands on the GPS tracker data for the American Solar Challenge last July. Above (for the 6 Challengers completing the stage) and below (for the Cruisers) are distance/speed charts for the run from Craters of the Moon to Burns, which seems the stage of the route with the best data (at this time of year I haven’t the time for a more detailed analysis). Click on the charts to zoom. Small coloured circles show end-of-day stops.

Stage times were 15:Western Sydney 8:05:16, 101:ETS Quebec 8:20:13, 2:Michigan 8:25:08, 55:Poly Montréal 8:42:52, 4:MIT 9:07:58, and 6:CalSol 9:30:12 for Challengers, and 828:App State 10:22:37, 559:Bologna 12:13:57, and 24:Waterloo 15:29:12 for Cruisers (note that Bologna was running fully loaded on solar power only, while the other Cruisers recharged from the grid).

The data has been processed by IOSiX. I’m not sure what that involved, but I’ve taken the data as gospel, eliminating any datapoints out of hours, off the route, or with PDOP more than 10. Notice that there are a few tracker “black spots,” and that trackers in some cars work better than in others. The small elevation charts are taken from the GPS tracker data, so they will not be reliable in the “black spots” (in particular, the big hill before Burns has been truncated – compare my timing chart).


Would y’all like to see a map?

The word y’all is used as a second person plural pronoun in the United States (although in my travels I have also heard it used as a polite singular). The map above (click to zoom) shows the average frequency of use by state, according to the 2003 Harvard Dialect Survey. The usage is primarily Southern.

English needs a second person plural pronoun, it seems to me. What do all-y’all think?

Image produced using the maps package of R. Other visualisations of the survey exist.


A Day in the Life of Solar Energy Racers

By special request, here is another day in the life post, this time for Swiss solar car team Solar Energy Racers (SER). The day is 29 September, the last day of the Sasol Solar Challenge. I am relying on information from a blog by SER strategy person Georg Russ, together with GPS data screen-scraped off the race tracker by a friend, and elevation data from the Shuttle Radar Topography Mission. As before, the horizontal axis of the chart represents distance.

The day began at Swellendam, and the team drove to the control stop at Bredasdorp, stopping there for 30 minutes the first time (it can be seen from the chart that SER was not quite so good as Nuon at maintaining a consistent speed). The team drove two loops, the first of them to Cape Agulhas (the southernmost point of the African continent, and the site of a picturesque lighthouse). It can be seen from the chart that they had to stop on the way (to repair a loose left rear wheel fairing – with duct tape, of course).

The team completed one more, shorter, loop, before heading on to the finish at Stellenbosch (Nuon drove that shorter loop three times). Knowing when to quit driving loops was an important strategy decision. The chart highlights the hilly nature of that final leg (going through part of the Cape Fold Belt), as well as some stops to change drivers.

Georg Russ notes an energy output for the day of 5.35 kWh (with 0.64 kWh recovered), and a photovoltaic input of 4.63 kWh, giving a net battery drain of 0.08 kWh. Pretty good!


A Day in the Life of Nuon Solar Team

This blog post is something a little different: it will use the GPS tracker data feed to describe a day in the life of Nuon Solar Team during the Sasol Solar Challenge. Specifically, it will describe Wednesday 26 September, which Nuon’s media team summarised in this 90-second video:

Wednesday 26 September (day 5 of the race) opened in Graaff-Reinet. On the Tuesday, Nuon had fallen 36 km behind Japanese team Tokai, due to electrical problems. The support engineers began work at 4:00 AM to return their car Nuna to tip-top condition. The morning was chilly, but sunny, which allowed some solar recharging of the batteries.

The plan for the day, as outlined in this livestream by media team-member Bianca Koppen, was to drive to the control stop in Jansenville faster than Tokai. At Jansenville there was an optional 65-km “loop” to Klipplaat and back. The plan was to drive this “loop” six times (Tokai was expected to do so only five times) and then continue to the end-of-day stop in Port Elizabeth, arriving there just before 5:00 PM. In line with this plan, Nuna sets off at around 85 km/h, soon overtaking Tokai:

The chart below (click to zoom) shows the progress of the day. The horizontal axis is distance, and the vertical axis of the main chart is the speed of the solar car. Underneath the main chart is an elevation plot. The letter A marks the start for the day.

The letter B marks the control stop at Jansenville, where Nuna initially stops for 30 minutes (as per the regulations; later stops will only be 5 minutes). Nuna then continues to the small town of Klipplaat, where the route simply loops and returns along the same road (see the map). However, the road to Klipplaat is uphill, and from Klipplaat is downhill. As the chart above shows, the shiny new “intelligent cruise control” adjusts the car’s speed to suit, running more slowly while climbing.

Point C on the chart is interesting. A few minutes into the 4th Jansenville–Klipplaat leg (shortly after noon), Nuon’s strategy team decides that the plan isn’t going to work. Either because of the weather, or the state of the car (I don’t know the reason), they decide that they will only drive five loops today, not six. The whole plan for the day is recalculated, so as to still get to Port Elizabeth just before 5:00 PM (but having used less energy). Instead of peaking around 87 km/h, the next two loops only peak around 70 km/h. The strategy team in the mission control (chase) vehicle must have been working furiously on this plan. On the chart, there is a sudden slow-down at 12:05 PM, but the new driving pattern is established just a few minutes after that. A good strategy team is critical to winning a race!

Point D on the chart marks the last stop in Jansenville, around 2:10 PM:

Race regulation 6.1 requires that a driver can operate the car for at most 2 hours. Given the distance to Port Elizabeth, Nuna stops briefly for a driver change at around 3:45 PM, shortly after this photograph was taken (point E on the chart):

And just before 5:00 PM, Nuna indeed reaches Port Elizabeth. After some more repair work, taking advantage of the energy saved during today’s run, and as the result of teamwork and skill, the plan to drive one more loop than Tokai succeeds the next day.

Of course, much more goes on during a typical day than this story suggests. People are feed and housed. Sick team-members are looked after. Media reports are produced. Nuna, go, go, go!