Replacing metal halide bulb
You cannot just replace the lamp, you also had to replace the coil so it matches the power of the lamp. Sometimes you had to replace even the starter with a matching type.

LED lamps available in shops typically don't have more than a few thousand lumen but you could look for LED retrofit lamps for street lighting on the net. They are available for E27, E40 and other sockets, too. Of course you had to remove the coil and the starter from the lamp fixture then.