How would I change the acceleration of this bodyposition/velocity (Vehicle)?

Hello all! Back again with another question. I have created a vehicle using bodygyro, bodyposition,etc. I used the scripts from the jeep model on the race prebuilt map and modified them slightly to meet my needs. Basically I am creating a gearing system for my vehicles. Depending on what gear you are in, depends on how fast you are able to go. So far I have everything working, the vehicle drives, turns, and even can shift gears. However, my issue is that the vehicle accelerates very quickly, almost max speed instantly. My shifting script is based on speed, if you aren't going fast enough to shift gears, it won't let you, but being as the vehicle accelerates instantly, players can just spam the shift gear button and would defeat the purpose of shifting.

I'm basically trying to figure out how to make the velocity of the vehicle take time to reach its max. I know about MaxThrust, MaxTorque, and MaxForce, however with the Jeep script, editing any value also affects the turning. I was able to make the script slowly accelerate by editing the Lerp value, however that also made the turning wonky, causing it to go really fast while turning, or not turn at all. My question is what values do I need to be adjusting, need to add into the current script, to make it not accelerate to max speed instantly? I know about D and P aswell, but changing those values didn't affect anything. My assumption is because those values are used in relation to destination. Obviously a vehicle driving around has no set destination, therefor it can't damper it.

LocalCarScript

--local camera = game.Workspace.CurrentCamera
local player = game.Players.LocalPlayer
local character = player.Character
local humanoidRootPart = character.HumanoidRootPart
local car = script:WaitForChild("Car").Value
local stats = car:WaitForChild("Configurations")
local Raycast = require(car.CarScript.RaycastModule)
local object = car.Chassis -- your object here
local gear = stats.Gear
--local cameraType = Enum.CameraType.Follow

local movement = Vector2.new()
local gamepadDeadzone = 0.14

car.DriveSeat.Changed:connect(function(property)
	if property == "Steer" then
		movement = Vector2.new(car.DriveSeat.Steer, movement.Y)
	elseif property == "Throttle" then
		movement = Vector2.new(movement.X, car.DriveSeat.Throttle)
	end
end)

-- Input begin
--game:GetService("UserInputService").InputBegan:connect(function(inputObject, gameProcessedEvent)
--	if not gameProcessedEvent then
--		if inputObject.KeyCode == Enum.KeyCode.W then
--			movement = Vector2.new(movement.X, 1)
--		elseif inputObject.KeyCode == Enum.KeyCode.A then
--			movement = Vector2.new(-1, movement.Y)
--		elseif inputObject.KeyCode == Enum.KeyCode.S then
--			movement = Vector2.new(movement.X, -1)
--		elseif inputObject.KeyCode == Enum.KeyCode.D then
--			movement = Vector2.new(1, movement.Y)
--		end
--	end
--end)
--
--game:GetService("UserInputService").InputChanged:connect(function(inputObject, gameProcessedEvent)
--	--if not gameProcessedEvent then
--		if inputObject.KeyCode == Enum.KeyCode.Thumbstick1 then
--			--Gamepad support because yay
--			if inputObject.Position.magnitude >= gamepadDeadzone then
--				movement = Vector2.new(movement.X, inputObject.Position.Y)
--			else
--				movement = Vector2.new(movement.X, 0)
--			end
--		elseif inputObject.KeyCode == Enum.KeyCode.Thumbstick2 then
--			if inputObject.Position.magnitude >= gamepadDeadzone then
--				movement = Vector2.new(inputObject.Position.X, movement.Y)
--			else
--				movement = Vector2.new(0, movement.Y)
--			end
--		end
--	--end
--end)
--
---- Input end
--game:GetService("UserInputService").InputEnded:connect(function(inputObject, gameProcessedEvent)
--	if inputObject.KeyCode == Enum.KeyCode.W then
--		if movement.Y == 1 then
--			movement = Vector2.new(movement.X, 0)
--		end
--	elseif inputObject.KeyCode == Enum.KeyCode.A then
--		if movement.X == -1 then
--			movement = Vector2.new(0, movement.Y)
--		end
--	elseif inputObject.KeyCode == Enum.KeyCode.S then
--		if movement.Y == -1 then
--			movement = Vector2.new(movement.X, 0)
--		end
--	elseif inputObject.KeyCode == Enum.KeyCode.D then
--		if movement.X == 1 then
--			movement = Vector2.new(0, movement.Y)
--		end
--	end
--end)

local force = 0
local damping = 0

local mass = 0

for i, v in pairs(car:GetChildren()) do
	if v:IsA("BasePart") then
		mass = mass + (v:GetMass() * 196.2)
	end
end

force = mass * stats.Suspension.Value
damping = force / stats.Bounce.Value

local bodyVelocity = Instance.new("BodyVelocity", car.Chassis)
bodyVelocity.velocity = Vector3.new(0, 0, 0)
bodyVelocity.maxForce = Vector3.new(0, 0, 0)

local bodyAngularVelocity = Instance.new("BodyAngularVelocity", car.Chassis)
bodyAngularVelocity.angularvelocity = Vector3.new(0, 0, 0)
bodyAngularVelocity.maxTorque = Vector3.new(0, 0, 0)

local rotation = 0

local function UpdateThruster(thruster)
	--Make sure we have a bodythrust to move the wheel
	local bodyThrust = thruster:FindFirstChild("BodyThrust")
	if not bodyThrust then
		bodyThrust = Instance.new("BodyThrust", thruster)
	end
	--Do some raycasting to get the height of the wheel
	local hit, position = Raycast.new(thruster.Position, thruster.CFrame:vectorToWorldSpace(Vector3.new(0, -1, 0)) * stats.Height.Value)
	local thrusterHeight = (position - thruster.Position).magnitude
	if hit and hit.CanCollide then
		--If we're on the ground, apply some forces to push the wheel up
		bodyThrust.force = Vector3.new(0, ((stats.Height.Value - thrusterHeight)^2) * (force / stats.Height.Value^2), 0)
		local thrusterDamping = thruster.CFrame:toObjectSpace(CFrame.new(thruster.Velocity + thruster.Position)).p * damping
		bodyThrust.force = bodyThrust.force - Vector3.new(0, thrusterDamping.Y, 0)
	else
		bodyThrust.force = Vector3.new(0, 0, 0)
	end
end

--Shifting Function
function onKeyPress(inputObject, gameProcessedEvent)
	if inputObject.KeyCode == Enum.KeyCode.E then
		if character.Humanoid.SeatPart == car.DriveSeat then
		if gear.Value < 18 then
			gear.Value = gear.Value + 1
			print(gear.Value)
		end
		end
	elseif inputObject.KeyCode == Enum.KeyCode.Q then
		if character.Humanoid.SeatPart == car.DriveSeat then
		if gear.Value > 0 and gear.Value <= 18 then
			gear.Value = gear.Value - 1
			print(gear.Value)
		end
		end
		end
end
 
game:GetService("UserInputService").InputBegan:connect(onKeyPress)

--A simple function to check if the car is grounded
local function IsGrounded()
	local hit, position = Raycast.new((car.Chassis.CFrame * CFrame.new(0, 0, (car.Chassis.Size.Z / 2) - 1)).p, car.Chassis.CFrame:vectorToWorldSpace(Vector3.new(0, -1, 0)) * (stats.Height.Value + 0.2))
	if hit and hit.CanCollide then
		return(true)
	end
	return(false)
end

--local oldCameraType = camera.CameraType
--camera.CameraType = cameraType

--spawn(function()
	while game:GetService("RunService").Heartbeat:wait() and car:FindFirstChild("DriveSeat") and character.Humanoid.SeatPart == car.DriveSeat do
		--game:GetService("RunService").RenderStepped:wait()
		if IsGrounded() then
			if movement.Y ~= 0 then
				local velocity = humanoidRootPart.CFrame.lookVector * movement.Y * stats.Speed.Value
				humanoidRootPart.Velocity = humanoidRootPart.Velocity:Lerp(velocity, 0.1)
				bodyVelocity.maxForce = Vector3.new(0, 0, 0)
			else
				bodyVelocity.maxForce = Vector3.new(mass / 2, mass / 4, mass / 2)
			end
			local rotVelocity = humanoidRootPart.CFrame:vectorToWorldSpace(Vector3.new(movement.Y * stats.Speed.Value / 50, 0, -humanoidRootPart.RotVelocity.Y * 5 * movement.Y))
			local speed = -humanoidRootPart.CFrame:vectorToObjectSpace(humanoidRootPart.Velocity).unit.Z
			rotation = rotation + math.rad((-stats.Speed.Value / 500) * movement.Y)
			if math.abs(speed) > 0.1 then
				rotVelocity = rotVelocity + humanoidRootPart.CFrame:vectorToWorldSpace((Vector3.new(0, -movement.X * speed * stats.TurnSpeed.Value, 0)))
				bodyAngularVelocity.maxTorque = Vector3.new(0, 0, 0)
			else
				bodyAngularVelocity.maxTorque = Vector3.new(mass / 4, mass / 2, mass / 4)
			end
			humanoidRootPart.RotVelocity = humanoidRootPart.RotVelocity:Lerp(rotVelocity, .1)
			
			--bodyVelocity.maxForce = Vector3.new(mass / 3, mass / 6, mass / 3)
			--bodyAngularVelocity.maxTorque = Vector3.new(mass / 6, mass / 3, mass / 6)
		else
			bodyVelocity.maxForce = Vector3.new(0, 0, 0)
			bodyAngularVelocity.maxTorque = Vector3.new(0, 0, 0)
		end
		
		for i, part in pairs(car:GetChildren()) do
			if part.Name == "Thruster" then
				UpdateThruster(part)
			end
		end
	end
	for i, v in pairs(car:GetChildren()) do
		if v:FindFirstChild("BodyThrust") then
			v.BodyThrust:Destroy()
		end
	end
	bodyVelocity:Destroy()
	bodyAngularVelocity:Destroy()
	gear.Value = 0
	--camera.CameraType = oldCameraType
	script:Destroy()
--end)