A modular front steering assembly (1000; 1100, 1200; 1300) adapted to integrate with a vehicle capable of zero-radius turn operation or near zero-radius turn operation, the vehicle having a prime mover, a subframe, an accelerator, a brake, a power source, and a pair of variable drive units each actuated by a respective swash plate, each variable drive unit driving one of a pair of axles, the modular front steering assembly comprising: a frame member (1022; 1122; 1222; 1322), non-integral with the subframe, having opposed ends and adapted for attachment to the subframe; a first wheel assembly (1024L; 1124L; 1224L; 1324L) attached to a first end of the frame member and pivotable about a first vertical steering axis and a second wheel assembly (1024R; 1124R, 1224R; 1324R) attached to a second end of the frame member and pivotable about a second vertical steering axis; a steering mechanism (1041; 1141; 1241; 1341) operatively connected to the first and second wheel assemblies, the steering mechanism comprising a steering column (1046; 1146; 1246; 1346) directly connected to the frame member and a steering input device; an electronic drive control system adapted to independently adjust the speed and rotational direction of the output from each variable drive unit located at a rear of the vehicle, comprising: a pair of electric actuators (1152L; 1152R; 1352L, 1352R), each adapted for attachment to one of the variable drive units and to adjust the position of the respective swash plate; a steering position sensor (1048; 1148; 1248; 1348); an accelerator position sensor (1172; 1372); a first speed sensor adapted for sensing the speed of one of the axles and a second speed sensor adapted for sensing the speed of the other of the axles; a controller (1150; 1350) in communication with the accelerator position sensor, the steering position sensor, the first speed sensor, the second speed sensor, and the pair of electric actuators, and the controller adapted to be in communication with the prime mover and the power source; and at least one wiring harness (1019; 1119; 1219; 1319) configured to place the controller in said communication; wherein the controller generates and transmits first control signals to the pair of electric actuators such that the respective swash plate is adjusted to independently control the speed of the output from each variable drive unit, the first control signals based on signals received by the controller from each of the accelerator position sensor, the steering position sensor, the first speed sensor, and the second speed sensor. a frame member (1022; 1122; 1222; 1322), non-integral with the subframe, having opposed ends and adapted for attachment to the subframe; a first wheel assembly (1024L; 1124L; 1224L; 1324L) attached to a first end of the frame member and pivotable about a first vertical steering axis and a second wheel assembly (1024R; 1124R, 1224R; 1324R) attached to a second end of the frame member and pivotable about a second vertical steering axis; a steering mechanism (1041; 1141; 1241; 1341) operatively connected to the first and second wheel assemblies, the steering mechanism comprising a steering column (1046; 1146; 1246; 1346) directly connected to the frame member and a steering input device; an electronic drive control system adapted to independently adjust the speed and rotational direction of the output from each variable drive unit located at a rear of the vehicle, comprising: a pair of electric actuators (1152L; 1152R; 1352L, 1352R), each adapted for attachment to one of the variable drive units and to adjust the position of the respective swash plate; a steering position sensor (1048; 1148; 1248; 1348); an accelerator position sensor (1172; 1372); a first speed sensor adapted for sensing the speed of one of the axles and a second speed sensor adapted for sensing the speed of the other of the axles; a controller (1150; 1350) in communication with the accelerator position sensor, the steering position sensor, the first speed sensor, the second speed sensor, and the pair of electric actuators, and the controller adapted to be in communication with the prime mover and the power source; and at least one wiring harness (1019; 1119; 1219; 1319) configured to place the controller in said communication; a pair of electric actuators (1152L; 1152R; 1352L, 1352R), each adapted for attachment to one of the variable drive units and to adjust the position of the respective swash plate; a steering position sensor (1048; 1148; 1248; 1348); an accelerator position sensor (1172; 1372); a first speed sensor adapted for sensing the speed of one of the axles and a second speed sensor adapted for sensing the speed of the other of the axles; a controller (1150; 1350) in communication with the accelerator position sensor, the steering position sensor, the first speed sensor, the second speed sensor, and the pair of electric actuators, and the controller adapted to be in communication with the prime mover and the power source; and at least one wiring harness (1019; 1119; 1219; 1319) configured to place the controller in said communication; wherein the controller generates and transmits first control signals to the pair of electric actuators such that the respective swash plate is adjusted to independently control the speed of the output from each variable drive unit, the first control signals based on signals received by the controller from each of the accelerator position sensor, the steering position sensor, the first speed sensor, and the second speed sensor.