Solo I events are high speed Time Trials; they may be run at race tracks, airport runways, or may be hillclimbs. Cars must be prepared to Road Racing safety standards (although in some cases roll bars are permitted instead of roll cages) and drivers must be SCCA members with appropriate Competition Licenses.competition licenses. Drivers will serve as cornerworkers, and learn to use Road Racing style flags; helmets will have to be Snell 85 or better (and loaners are unlikely to be available); drivers of prepared and mod cars will have to have approved fire resistant clothing; and all open cars shall be required to have an appropriate roll bar.
More information on Solo Trials will be forthcoming from the SCCA in the near future. See the article in the February 1995 issue of SportsCar for that which has been published to date.
Solo II events are a low to medium speed event; they are often run on parking lots and airport runways, although street events and events at Go Kart tracks sometimes take place. Generally a course will be defined using traffic cones; time penalties will charged for disturbing cones. In most regions, the penalty is 2 seconds per cone, although in some places it may be 1 second. There is an upper speed guideline for Solo II which is intended to keep speeds in a domain that most drivers might have encountered on the streets and highways; the fastest cars at a Solo II should not get much over 70mph.
At the regional level, Solo II is very much a grassroots sport, and SCCA membership is not required to participate. At the Divisional and National level, drivers must be SCCA members to compete.
Pro Solo events use the same sites and speed guidelines as Solo II, but in a somewhat different format. The format consists of two mirror-image courses with a drag-strip start, complete with a christmas tree. Each competitor receives 6 runs on each side over the course of two days. After that competition, the top 32 drivers from each of the 17 classes compete in a single-elimination tournament, with a handicapping system to equalize the cars from different classes. Unlike the amateur Solo I and Solo II events, Pro Solo events pay prize money. Competitors must be SCCA members and hold a Pro Solo license, although the latter requirement is waived for a competitors first event in a given season. Pro Solo is a travelling series, typically with 10 events plus the season finale.