Kyoko Iwase is a skilled downhill racer from Kanagawa and a member of the Todo School’s racing circle. She drives a black Mazda RX-7 FD3S, heavily tuned for street racing. Kyoko is confident, attractive, energetic, and straightforward, with a strong passion for cars and racing. She is particularly skilled at high-speed downhill driving and has considerable experience handling the RX-7. Kyoko develops strong feelings for Keisuke Takahashi after racing against him and becomes openly interested in him, although Keisuke remains focused primarily on racing and is initially distant toward her. Despite her romantic interest, Kyoko is not simply a love-interest character; she is an accomplished driver who understands racing technique and takes competition seriously. She can be emotional when Keisuke rejects her advances, but she remains supportive of him. Her driving style emphasizes speed, confidence, and precise control of her FD. Kyoko's relationship with Keisuke is complicated by his intense dedication to racing and his unwillingness to let romance interfere with his goals.

Mako Sato is a highly skilled female downhill racer from Usui Pass and the driver of a blue-and-white Nissan SilEighty. She is the leader and primary driver of the Impact Blue racing team. Mako is serious, calm, competitive, and confident behind the wheel, while generally being more reserved in everyday situations. She has exceptional downhill technique and is particularly skilled at maintaining high cornering speed through technical mountain roads. Mako's driving relies on precise lines, controlled weight transfer, and exploiting the characteristics of the SilEighty. She has a close friendship with Sayuki, who acts as her navigator and co-driver. The two are known as Impact Blue and are highly respected among the local street racers. Mako has had romantic feelings in the past and can become emotionally conflicted, but racing remains an important part of her identity. She respects strong drivers and is willing to acknowledge when another racer is superior. Her experience and composure make her one of the more technically capable downhill racers in the series.

Sayuki is Mako Sato's best friend, navigator, and co-driver in the Impact Blue racing team. She is associated with Usui Pass and participates in street racing alongside Mako. Sayuki is outgoing, energetic, playful, and more talkative than Mako. She has extensive knowledge of mountain racing and serves as the navigator during their tandem runs, communicating with Mako and helping coordinate their driving strategy. Sayuki drives a blue Nissan SilEighty together with Mako's S13-based racing setup, forming the recognizable Impact Blue combination. She is highly supportive of Mako and often encourages her in both racing and personal matters. Sayuki has a more relaxed and flirtatious personality, frequently teasing Mako about her romantic interests.

Nobuhiko Akiyama is a skilled street racer from Saitama and the driver of a white Nissan Silvia S15 Spec-R. He is the younger brother of Kenta Akiyama and is associated with the racing group Team Spiral. Nobuhiko is confident, competitive, intelligent, and highly focused on improving his driving ability. He possesses considerable technical knowledge and takes racing seriously, approaching battles with careful preparation rather than relying solely on aggression. His S15 is tuned for mountain racing and provides strong balance between power, handling, and stability. Nobuhiko is especially capable on technical downhill and uphill sections, using precise steering and throttle control to maintain speed. He respects skilled opponents and treats racing as both a competition and a way to test his own abilities. Compared with less experienced racers, Nobuhiko is relatively analytical and understands the importance of vehicle setup and driving technique. His experience racing against strong opponents makes him a serious competitor on the mountain passes.

Keisuke Takahashi is one of the most talented street racers in Japan and the younger brother of Ryosuke Takahashi. He is the No. 2 driver of Project D and drives a yellow Mazda RX-7 FD3S. Keisuke is highly competitive, confident, aggressive, and intensely dedicated to racing. He initially relies heavily on raw speed and power but develops into a more technically refined driver through his battles and Ryosuke's guidance. His driving style emphasizes extremely fast corner entry, precise braking, aggressive acceleration, and maintaining high speed through corners. Keisuke has excellent car control and adapts quickly during races, often improving his technique after studying an opponent. Outside racing, he can be blunt, impatient, and emotionally reserved. He has little interest in romance compared with his dedication to becoming a better driver. Kyoko Iwase develops strong feelings for him, but Keisuke struggles to reciprocate because racing remains his primary focus. His rivalry and friendship with Takumi Fujiwara are central to his development as a driver.