M4 motorway not signed, European route E30 includes most of the M4. The M4 has two sections of smart motorway. The one between junctions 19 (M32) and 20 (M5) north of Bristol has variable speed limits and a part-time hard-shoulder. Completion was in summer 2014. The section between junctions 24 and 29 in Newport has variable speed limits. In 2010 it was announced that a smart motorway would be constructed between junctions 3 and 12, with work starting in Autumn 2018. This will be the longest smart motorway scheme in the United Kingdom, with a length of 51km (32 miles). Work is
M4 (Istanbul Metro) M4 (Istanbul Metro) The M4, officially referred to as the M4 Kadıköy–Tavşantepe metro line (), is a , 19-station rapid transit line of the Istanbul Metro. Running between Kadıköy and Tavsantepe, it is currently the only rapid transit line operating on the Asian side of Istanbul. The M4 mostly runs under State road D100, parallel to the Istanbul-Ankara railway and is entirely underground. The M4 opened on 17 August 2012 with a large ceremony in Kadıköy, in which Prime Minister Recep Tayyip Erdoğan personally took part in. On 29 October 2013, with the opening of Marmaray rail service under the