A motorcycle, comprising: - a motorcycle body (2,3,4) having a front part, a tail part and a central part comprised between the front part and the tail part; - at least two wheels (5,6), constrained to the motorcycle body (2,3,4), comprising a front wheel and a rear wheel; - a traction engine, constrained to the motorcycle body (2,3,4) and operatively connected to at least one of the wheels (5,6); - at least one optical signalling device (15,64) fixed to the motorcycle body (2,3,4), arranged and oriented so as to be visible by a vehicle that is following the motorcycle; the optical signalling device (15,64) is, or at least comprises, rear direction indicators; - an electronic control unit of the optical signalling device (15,64) operatively connected to the optical signalling device (15,64); - an obstacle sensor fixed to the motorcycle body (2,3,4) and operatively connected to the electronic control unit; - at least an additional acoustic, optical or tactile signalling device configured to inform the driver of the motorcycle of the presence of a frontal obstacle and/or of the risk of collision with a vehicle behind; wherein: - the obstacle sensor comprises an optical sensor, and is arranged on the front part of the motorcycle body (2,3,4) and oriented so that the output signal supplied to the electronic control unit carries information correlated to the presence of obstacles placed in front of the motorcycle; - the electronic control unit is adapted and configured to receive at least one output signal supplied by the obstacle sensor, verifying whether said output signal meets at least one logical activation condition and, in such case, turning on the optical signalling device (15,64) to signal a risk of collision with the motorcycle to the vehicle which follows the motorcycle; - the obstacle sensor and the electronic control unit are adapted and configured to detect and recognise an optical signalling emitted frontally with respect to the motorcycle, wherein said optical signalling is a luminous optical signalling and is due to: - the lighting of a brake light of a vehicle which precedes the motorcycle; and/or - the lighting of a stop light or caution light emitted by a traffic light placed frontally with respect to the motorcycle. - a motorcycle body (2,3,4) having a front part, a tail part and a central part comprised between the front part and the tail part; - at least two wheels (5,6), constrained to the motorcycle body (2,3,4), comprising a front wheel and a rear wheel; - a traction engine, constrained to the motorcycle body (2,3,4) and operatively connected to at least one of the wheels (5,6); - at least one optical signalling device (15,64) fixed to the motorcycle body (2,3,4), arranged and oriented so as to be visible by a vehicle that is following the motorcycle; the optical signalling device (15,64) is, or at least comprises, rear direction indicators; - an electronic control unit of the optical signalling device (15,64) operatively connected to the optical signalling device (15,64); - an electronic control unit of the optical signalling device (15,64) operatively connected to the optical signalling device (15,64); - an obstacle sensor fixed to the motorcycle body (2,3,4) and operatively connected to the electronic control unit; - at least an additional acoustic, optical or tactile signalling device configured to inform the driver of the motorcycle of the presence of a frontal obstacle and/or of the risk of collision with a vehicle behind; - the obstacle sensor comprises an optical sensor, and is arranged on the front part of the motorcycle body (2,3,4) and oriented so that the output signal supplied to the electronic control unit carries information correlated to the presence of obstacles placed in front of the motorcycle; - the electronic control unit is adapted and configured to receive at least one output signal supplied by the obstacle sensor, verifying whether said output signal meets at least one logical activation condition and, in such case, turning on the optical signalling device (15,64) to signal a risk of collision with the motorcycle to the vehicle which follows the motorcycle; - the obstacle sensor and the electronic control unit are adapted and configured to detect and recognise an optical signalling emitted frontally with respect to the motorcycle, wherein said optical signalling is a luminous optical signalling and is due to: - the lighting of a brake light of a vehicle which precedes the motorcycle; and/or - the lighting of a stop light or caution light emitted by a traffic light placed frontally with respect to the motorcycle. - the lighting of a brake light of a vehicle which precedes the motorcycle; and/or - the lighting of a stop light or caution light emitted by a traffic light placed frontally with respect to the motorcycle.