A criticism of PRT systems: [1]<p>Classic problems:<p>- Capacity isn&#x27;t high.  One track equals about one freeway lane.<p>- One broken vehicle stalls the whole track.<p>- Real guideways are usually much bigger than pictures of proposed guideways.
You need emergency walkways, rescue access, and earthquake resistance. This is also true of monorails.<p>- Somebody has to clean all those vehicles.<p>Light guideway systems do exist. Intamin, the roller coaster manufacturer, also makes monorails. Theirs are as narrow as roller coaster tracks.[2]  Here&#x27;s their towing and rescue vehicle in action.[3]  But their systems are low-capacity and slow. Japan has many monorails with serious passenger capacity, but the guideways are big.[4]  One design has a flat guideway that would work for a PRT.<p>[1] <a href="http:&#x2F;&#x2F;www.lightrailnow.org&#x2F;facts&#x2F;fa_prt001.htm" rel="nofollow">http:&#x2F;&#x2F;www.lightrailnow.org&#x2F;facts&#x2F;fa_prt001.htm</a>
[2] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=7HInUerMfWU" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=7HInUerMfWU</a>
[3] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=70q_CoLT3Eo" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=70q_CoLT3Eo</a>
[4] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=lUpIl25q1nk" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=lUpIl25q1nk</a>