▁words , ▁no ▁one ▁was ▁pay ing ▁to ▁be ▁carried . ▁The ▁law ▁was ▁changed ▁in ▁ 1 9 9 2 ▁so ▁that ▁all ▁drivers ▁of ▁large ▁bus es ▁had ▁to ▁hold ▁a ▁PC V ▁( PS V ) ▁lic ence , ▁but ▁anyone ▁who ▁had ▁driven ▁large ▁bus es ▁could ▁apply ▁for ▁grand father ▁rights ▁to ▁carry ▁on ▁doing ▁so . ▁ ▁Some ▁M OT ▁test ▁standards ▁in ▁the ▁UK ▁do ▁not ▁apply ▁to ▁vehicles ▁first ▁registered ▁prior ▁to ▁the ▁implementation ▁of ▁the ▁legisl ation ▁that ▁introduced ▁them . ▁For ▁example , ▁vehicles ▁first ▁registered ▁prior ▁to ▁January ▁ 1 , ▁ 1 9 7 3 ▁are ▁ex empt ▁from ▁the ▁requirement ▁to ▁use ▁retro - reflect ive ▁yellow / white ▁vehicle ▁registration ▁pl ates ▁and ▁vehicles ▁first ▁registered ▁prior ▁to ▁January ▁ 1 , ▁ 1 9 6 5 ▁are ▁ex empt ▁from ▁seat ▁bel t ▁standards / leg isl ation ▁unless ▁they ▁have ▁been ▁ret ros pect ively ▁fitted . ▁In ▁some ▁U . S . ▁states , ▁the ▁ins pection / main ten ance ▁( I / M ) ▁programs ▁for ▁motor ▁vehicle ▁emission ▁testing ▁have ▁a ▁rolling ▁ch ass is ▁exem ption , ▁e . g . ▁a ▁motor ▁vehicle ▁model ▁ 2 5 ▁years ▁old ▁or ▁more ▁is ▁ex empt ed ▁from ▁emission ▁tests . ▁ ▁Sports ▁ ▁In ▁ 1 9 2 0 , ▁when ▁Major ▁League ▁Baseball ▁introduced ▁the ▁prohib ition ▁of ▁the ▁sp it ball , ▁the ▁league ▁recognized ▁that ▁some ▁professional ▁pitch ers