An adjustable pedal assembly for operating a push rod that activates a functional system of a vehicle, the adjustable pedal assembly configured for movement between a first position and a second position, the adjustable pedal assembly comprising: a pedal arm comprising an elongated lever structure with a first end and a second end; a pedal plate provided on the second end of the elongated lever structure of the pedal arm for depression by a foot of a driver; a vehicle mounting bracket; a pivot member configured for pivoting relative to the vehicle mounting bracket about a first fixed pivot axis; an activation link, a first end of the activation link being connected to the pivot member for pivoting therewith about the first fixed pivot axis and the second end of the activation link being connected to the elongated lever structure of the pedal; a link member having a first portion pivotally connected at a second fixed pivot axis to the activation link and a second portion connected to a booster receiver for connection to the push rod that activates the functional system of the vehicle; the first end of the elongated lever structure configured for pivoting with an adjustable slide pin about a third variable pivot axis; and characterised in that the activation link and the link member each having a slot therein for movement of the adjustable slide pin therein, the third variable pivot axis of the adjustable slide pin configured for adjustment between a first pivot position and a second pivot position in each slot, and wherein movement of the adjustable slide pin between the first pivot position and the second pivot position varies a linear adjustment trajectory of the pedal arm relative to the pivot member in the first position and the second position of the adjustable pedal assembly, while a ratio between a distance between the first fixed pivot axis and the pedal plate and a distance between the first fixed pivot axis and the booster receiver remains substantially constant. a pedal arm comprising an elongated lever structure with a first end and a second end; a pedal plate provided on the second end of the elongated lever structure of the pedal arm for depression by a foot of a driver; a vehicle mounting bracket; a pivot member configured for pivoting relative to the vehicle mounting bracket about a first fixed pivot axis; an activation link, a first end of the activation link being connected to the pivot member for pivoting therewith about the first fixed pivot axis and the second end of the activation link being connected to the elongated lever structure of the pedal; a link member having a first portion pivotally connected at a second fixed pivot axis to the activation link and a second portion connected to a booster receiver for connection to the push rod that activates the functional system of the vehicle; the first end of the elongated lever structure configured for pivoting with an adjustable slide pin about a third variable pivot axis; and characterised in that the activation link and the link member each having a slot therein for movement of the adjustable slide pin therein, the third variable pivot axis of the adjustable slide pin configured for adjustment between a first pivot position and a second pivot position in each slot, and wherein movement of the adjustable slide pin between the first pivot position and the second pivot position varies a linear adjustment trajectory of the pedal arm relative to the pivot member in the first position and the second position of the adjustable pedal assembly, while a ratio between a distance between the first fixed pivot axis and the pedal plate and a distance between the first fixed pivot axis and the booster receiver remains substantially constant.