Believe it or not, I know far too many lawyers who don't request discovery in their client's cases. They argue, the person is pleading guilty or getting ARD so why should I request it?
Every defendant, under Rule 573, is permitted to "demand" discovery from the prosecution. The information must be turned over to the defendant's Chester County DUI lawyer provided it is material to the instant case. Any evidence that is favorable to the defendant and is material to either guilt or punishment is required to be sent. In addition, any written confession or inculpatory statement and the prior criminal record of the defendant.
You are not, unfortunately, entitled to discovery prior to the Preliminary Hearing. The defendant is entitled to file a motion within 14 days after the arraignment for this paperwork and it must set forth the good faith reasons whey the material is important to the case. In the case of a DUI, it would include any video of the stop, Field Sobriety Tests, and arrest, lab reports and results, police reports, photos, and statements from witnesses.
At the Preliminary Hearing in Chester County, however, you should be provided a copy of the blood, breath, or urine test results as they must be entered at the Preliminary Hearing to sustain the Commonwealth's burden of proof. Issues with a grand jury are typically handled through Rules 230 (Disclosure of Testimony Before Investigating Grand Jury) and 556.10 (Secrecy; Disclosure).
Some discovery, however, is discretionary. This includes names and addresses of eyewitnesses, some recorded or written statements, and photographs and or written materials (like journals). The Commonwealth bears a continuing duty to disclose any and all additional discovery that comes to light.
If discovery is not provided, the court may order such a party to permit discovery or inspection, may grant a continuance, may prohibit the Commonwealth from introducing the non-disclosed evidence or may enter additional orders that fit under the circumstances. If your attorney does not have discovery and their repeated attempts fail, it may make sense to file a Motion to Compel to get the information.