A vehicle braking system (120, 220, 320) comprising: a master cylinder (132, 232, 332); a wheel cylinder (130, 230, 330, 430, 530, 630); a primary braking unit (122, 222, 322) including a first pressure generating unit (134, 234, 334) distinct from the master cylinder (132, 232, 332) and operable to actuate a braking action at the wheel cylinder (130, 230, 330, 430, 530, 630) in a primary mode of operation, and an outlet port (190, 290, 390) connecting the primary braking unit (122, 222, 322) to the wheel cylinder (130, 230, 330, 430, 530, 630); and a secondary braking unit (124, 224, 324, 424, 524, 624) including a second pressure generating unit (150, 151, 250, 251, 350, 352, 450, 451, 551, 651) distinct from the master cylinder (132, 232, 332) and operable to actuate a braking action at the wheel cylinder (130, 230, 330, 430, 530, 630) in a secondary mode of operation, wherein the secondary braking unit (124, 224, 324, 424, 524, 624) has an inlet port (192, 292, 392, 492, 592, 692) connected to the outlet port (190, 290, 390) of the primary braking unit (122, 222,322); and wherein the primary braking unit (122, 222,322) includes one or more ABS valves (144, 146, 244, 246, 344, 346) operable to control traction control and anti-lock braking in the primary mode of operation and located between the first pressure generating unit (134, 234, 334) and the outlet port (190, 290, 390) of the primary braking unit (122, 222,322), wherein the secondary braking unit (124, 224, 324, 424, 524, 624) is located between the one or more ABS valves (144, 146, 244, 246, 344, 346) and the wheel cylinder (130, 230, 330, 430, 530, 630); characterized in that the secondary braking unit (124, 224, 324, 424, 524, 624) further includes a separation valve (176, 276, 376, 476, 576, 676) positioned between the inlet port (192, 292, 392, 492, 592, 692) and the wheel cylinder (130, 230, 330, 430, 530, 630), wherein the separation valve (176, 276, 376, 476, 576, 676) is in an open position in the primary mode of operation and is in a closed position in the secondary mode of operation. a master cylinder (132, 232, 332); a wheel cylinder (130, 230, 330, 430, 530, 630); a primary braking unit (122, 222, 322) including a first pressure generating unit (134, 234, 334) distinct from the master cylinder (132, 232, 332) and operable to actuate a braking action at the wheel cylinder (130, 230, 330, 430, 530, 630) in a primary mode of operation, and an outlet port (190, 290, 390) connecting the primary braking unit (122, 222, 322) to the wheel cylinder (130, 230, 330, 430, 530, 630); and a secondary braking unit (124, 224, 324, 424, 524, 624) including a second pressure generating unit (150, 151, 250, 251, 350, 352, 450, 451, 551, 651) distinct from the master cylinder (132, 232, 332) and operable to actuate a braking action at the wheel cylinder (130, 230, 330, 430, 530, 630) in a secondary mode of operation, wherein the secondary braking unit (124, 224, 324, 424, 524, 624) has an inlet port (192, 292, 392, 492, 592, 692) connected to the outlet port (190, 290, 390) of the primary braking unit (122, 222,322); and wherein the primary braking unit (122, 222,322) includes one or more ABS valves (144, 146, 244, 246, 344, 346) operable to control traction control and anti-lock braking in the primary mode of operation and located between the first pressure generating unit (134, 234, 334) and the outlet port (190, 290, 390) of the primary braking unit (122, 222,322), wherein the secondary braking unit (124, 224, 324, 424, 524, 624) is located between the one or more ABS valves (144, 146, 244, 246, 344, 346) and the wheel cylinder (130, 230, 330, 430, 530, 630); characterized in that the secondary braking unit (124, 224, 324, 424, 524, 624) further includes a separation valve (176, 276, 376, 476, 576, 676) positioned between the inlet port (192, 292, 392, 492, 592, 692) and the wheel cylinder (130, 230, 330, 430, 530, 630), wherein the separation valve (176, 276, 376, 476, 576, 676) is in an open position in the primary mode of operation and is in a closed position in the secondary mode of operation.