The types segment classifies tailpipe emissions by propulsion technology, highlighting the internal combustion engine (ICE) variants that directly affect exhaust composition. Conventional ICE vehicles, employing naturally aspirated gasoline or diesel engines, remain the largest contributor, encompassing roughly 55 % of total tailpipe emissions due to their widespread adoption and legacy fleet stock. Turbocharged ICE models, which enhance power density through forced induction, account for about 25 % of emissions; the increased combustion pressure often raises nitrogen oxide (NOx) levels despite improved fuel efficiency. Direct Injection ICE vehicles, representing approximately 15 % of the market, deliver precise fuel delivery but can generate higher particulate matter (PM) emissions without after‑treatment. Hybrid ICE systems, combining an ICE with an electric motor, contribute the remaining 5 %, reflecting their limited market penetration yet notable emission reductions relative to pure ICEs. This market taxonomy underscores how each propulsion type shapes the aggregate tailpipe emission landscape, informing regulatory frameworks and technology road‑maps.