Fix (needs more testing) in btRigidBody::setCenterOfMassTransform, assign m_interpolationWorldTransform = xform; instead of m_worldTransform;

Thanks Jay for reporting
Added braking capability to btRaycastVehicle, see Bullet/Demos/VehicleDemo/VehicleDemo.cpp
Added glutKeyboardUpFunc, for vehicle demo (keep accelerating/breaking, until key released/UP). Hope this is compatible with most GLUT implementations.

Demos/OpenGL/DemoApplication.cpp

@@ -368,6 +368,13 @@ void DemoApplication::keyboardCallback(unsigned char key, int x, int y)
 
 }
 	
+void DemoApplication::specialKeyboardUp(int key, int x, int y)
+{
+
+		glutPostRedisplay();
+
+}
+
 void DemoApplication::specialKeyboard(int key, int x, int y)	
 {
 	(void)x;

Demos/OpenGL/DemoApplication.h

@@ -155,6 +155,8 @@ public:
 
 	virtual void specialKeyboard(int key, int x, int y);
 
+	virtual void specialKeyboardUp(int key, int x, int y);
+
 	virtual void reshape(int w, int h);
 
 	virtual void mouseFunc(int button, int state, int x, int y);

Demos/OpenGL/GlutStuff.cpp

@@ -32,6 +32,12 @@ static void glutSpecialKeyboardCallback(int key, int x, int y)
 	gDemoApplication->specialKeyboard(key,x,y);
 }
 
+static void glutSpecialKeyboardUpCallback(int key, int x, int y)
+{
+	gDemoApplication->specialKeyboardUp(key,x,y);
+}
+
+
 static void glutReshapeCallback(int w, int h)
 {
 	gDemoApplication->reshape(w,h);
@@ -75,6 +81,8 @@ int glutmain(int argc, char **argv,int width,int height,const char* title,DemoAp
 
 	glutKeyboardFunc(glutKeyboardCallback);
 	glutSpecialFunc(glutSpecialKeyboardCallback);
+	glutSpecialUpFunc(glutSpecialKeyboardUpCallback);
+
 	glutReshapeFunc(glutReshapeCallback);
     //createMenu();
 	glutIdleFunc(glutMoveAndDisplayCallback);