їхати / їздити

In Ukrainian, verbs of motion come in pairs. Unlike English 'go', Ukrainian strictly distinguishes vehicular travel (їхати / їздити) from walking on foot (іти / ходити). Note that їхати and їздити mean 'to go by vehicle' (as a passenger or driver), not strictly 'to drive' (operating a vehicle is водити or керувати).

1. їхати (Determinate)
Use this when the action is:

• Happening right now in a specific direction (e.g., 'I am going [by vehicle] to work now').
• A specific, planned trip in the future.
• A single trip in the past that was in progress or interrupted (e.g., 'Я їхав на роботу, коли...' - 'I was going to work when...').

2. їздити (Indeterminate)
Use this when the action is:

• Habitual or repeated (e.g., 'I go to Lviv every month').
• A completed round-trip in the past (e.g., 'I went to the store [and came back]'). Note: Even for completed round-trips, you must use directional prepositions (e.g., я їздив у магазин), not locational ones (do not say 'я їздив в магазині').
• Aimless or multi-directional (e.g., 'riding around the city').

Perfective Counterparts:
To express a single, completed trip or a simple future action, use the perfective verb поїхати (e.g., 'я поїду' instead of 'я буду їхати'). For the indeterminate verb, the perfective form is поїздити, which means 'to drive or travel around for a while and then stop' (e.g., 'я поїжджу').

Conjugation Nuances:
Both verbs are imperfective. Note the stem change in the present tense for їхати (х → д): я їду, ти їдеш, вони їдуть. Also note the consonant mutation in the first person singular of їздити: я їжджу (зд → ждж). This mutation ONLY happens in the 'я' form; the rest of the conjugation uses the standard stem (e.g., ти їздиш, він їздить, вони їздять). In the past tense, the forms are regular: їхати (їхав, їхала, їхали) and їздити (їздив, їздила, їздили).

Transport and Destination:
To specify the vehicle, the formal standard is the instrumental case (автобусом, поїздом, машиною). However, in modern everyday speech, на + locative is also very common for declinable vehicles (на автобусі, на поїзді). For indeclinable foreign words like метро or таксі, you should use prepositions (на метро, в метро, на таксі) to clarify their syntactic role, as this is completely standard and grammatically correct.

To specify the destination, remember that verbs of motion answer the question Куди? (Where to?), not Де? (Where at?). This requires directional prepositions:

• For people and often cities, use до + genitive (їду до мами, їду до Києва).
• For countries, buildings, and events, use accusative with в/у or на (їду в Україну, їду в офіс, їду на роботу). Note that cities can also take в/у + accusative (їду в Київ).