An air carrier crew was cleared to taxi from LAX Runway 6R; left on Taxiway E; and right on Taxiway R. The crew entered Taxiway E-13 which was mistaken for Taxiway R claiming that the taxiways are close together and that the signage does not clearly differentiate R from E-13 coming from the West.

Narrative

Initially told to expect 7L LAX. Briefed approach and expected taxi in. On approximately a 10-12 mile final we were given 6R; changed ILS frequency; input correct runway and approach in the FMC; and we intercepted the localizer and landed uneventfully. We were very light so we stopped without using much runway. Upon reaching taxi speed I saw a reverse high-speed taxiway (E-13) and requested to exit there. Ground said approved; turn left on Echo and right on Romeo; we acknowledged and started our taxi to Romeo. There is considerable construction on the airport and lots of additional lights. We started our right turn onto what I thought was Romeo but it was actually E-13; a ramp entry. There is a taxi sign that states Romeo taxiway adjacent to both Romeo and E-13; which led to the quick turn into E-13. We quickly realized our mistake; I stopped the aircraft and told ground. They asked if we could make the turn back to the taxiway. I said unable. I have read far too many reports where we have taken a minor taxi problem and turned it into a major problem by trying to 'fix' the issue. Since there was no way to turn around; a tug was called and we were pushed out back to the taxi way. Upon reaching the gate I was met by an Airport Operation Supervisor. I was informed that this is a recurring problem; he said that they had 3 aircraft taxi into E-13 in one hour one day; and they are trying to resolve the confusing signage to prevent this from occurring as frequently as it has.