2018, Las Vegas, spring races, there are four horizontally-aligned blue bulbs, representing the four lanes (Charlotte and Las Vegas April races are four-lane races). Two weeks later at Royal Purple Raceway in Baytown, Texas, the current standard Christmas Tree was adopted, with only two blue bulbs for the two lanes. Starting in 2016 for selected bracket races, CompuLink debuted the TruStart system for staggered start races. Prior to that, if the first driver left before the green, the light turned red automatically and the other driver was shown a green light, regardless of the infraction. Timing system manufacturers Since 1984, the NHRA officially uses CompuLink timing systems at venues on their professional drag racing circuit (includes the Christmas Tree, control units, timing sensors, cables, program software and time slip printer). Many divisional tracks for both the NHRA and IHRA also use CompuLink, but current timing system manufacturers of similar operations including Accutime, TSI, PortaTree and RaceAmerica among others can be seen at various drag strips throughout the world so long as these timing systems comply to rules and regulations set forth by the respective drag racing organizations for which they are members. There are still a few drag strips which continue to use the much older Chrondek timing system, although the company was sold to Daktronics in the 1980s and parts for that system are no longer made. Most drag racing time scoreboards currently seen at the tracks are provided by Daktronics, RaceAmerica or Accutime. References Auto racing equipment