What’s Halachically better, to drive to the hospital oneself or to call an ambulance?[1]

Emergency: In all cases of emergency that medical assistance is immediately required even prior to reaching the hospital then obviously an ambulance is to be taken.

Non-Emergency: If the matter is not this urgent then it is better for a religious Jew to drive the patient to the hospital rather than call an ambulance.[2] [However, if one knows that the driver is a gentile, then it is better to call an ambulance then to drive oneself.[3] Likewise, if one will not be able to beware from all the unnecessary matters of Shabbos desecration involved in the driving, then it is better to take a taxi or ambulance.[4] Thus, for example, if one will be forced into parking his car and turning off the engine upon arrival at the hospital, which contains no allowance of Pikuach Nefesh, then it is better to take an ambulance.] If no religious Jew is available to drive then it is better to call an ambulance then have a non-religious Jew [i.e. taxi driver] do the driving.[5]

[1] Piskeiy Teshuvos 328:12; See Toras Hayoledes Chapter 10:1; 20-21, 24

[2] The reason: As by doing so one diminishes in the transgression of making the phone call, as well as the ambulance drivers usually are not careful in matters of desecration of Shabbos which are not needed, such as driving back to the station, while a religious driver will be. [Now, although the Ketzos Hashulchan 140: footnote 3 rules the opposite that it is better to take an ambulance then to have one drive, this was only because back then the cars would drive back home, which was forbidden, while the ambulances would drive back to their station which was permitted due to that they need to be on call. However today even the Ketzos Hashulchan would agree that it is better for a religious Jew to drive as the religious driver will not drive back home. Thus, there is desecration of Shabbos being saved.]

Matters to beware upon driving to the hospital: See Toras Hayoledes Chapter 20 for laws relating to the turning on of lights in car upon opening the door; Chapter 21 for details relating to 1) carrying the keys; 2) taking a  phone; 3) opening and closing the doors; 4) placing on seat belt; 5) Turning on lights 6) Turning on air in car; 7) How to drive with a Shinuiy; 8) How to drive, pace and breaks; 9) Turning of the engine upon arrival.

[3] Piskeiy Teshuvos 328:13 and Toras Hayoledes ibid

Opinion of Admur: Tzaruch Iyun if according to Admur who rules that a Jew is to do the desecration over a gentile, if this applies even in this case [that a Jew should do the driving rather than call a gentile ambulance] being that here people will simply think that the gentile ambulance was contacted not because that a Jew cannot do the driving but rather because it is an emergency, and there is thus no longer a worry that people may come to think that the Jew cannot drive. Furthermore, it is evident to all that the Jew had to call the gentile ambulance and it is thus evident to all that a Jew may desecrate Shabbos to save a life. Thus, it seems clear that in a case that a gentile ambulance driver is available he should be contacted rather than have a religious Jew drive to the hospital, being that although one adds in the phone call he nevertheless diminishes the entire transgression of driving. To note that so rules Piskeiy Teshuvos 328:13 and Toras Hayoledes ibid

[4] See previous footnotes!

[5] As he will do extra Shabbos transgressions unnecessarily; See Toras Hayoledes 13:8-9