PRIME MEDICAL SERVICES, INC.
                              AMENDED AND RESTATED
                             1993 STOCK OPTION PLAN


                            Scope and Purpose of Plan
                            -------------------------

         Prime Medical Services, Inc., a Delaware corporation (the
"Corporation"),  has adopted this Amended and Restated 1993 Stock Option Plan
(the "Plan") to provide for the granting of:

         (a)  Incentive Options (hereinafter defined) to certain key
              employees of the Corporation, or of its Affiliates
              (hereinafter defined), and

         (b)  Non-Incentive Options (hereinafter defined) to certain key
              employees and nonemployee directors of the Corporation or of
              its Affiliates.

         The purpose of the Plan is to provide an incentive for Eligible
Individuals (hereinafter defined) to remain in the service of the Corporation or
its Affiliates, to extend to them the opportunity to acquire a proprietary
interest in the Corporation so that they will apply their best efforts for the
benefit of the Corporation, and to aid the Corporation in attracting able
persons to enter the service of the Corporation and its Affiliates. On June 10,
1998, the shareholders of the Corporation approved an amendment increasing the
number of shares of Common Stock (as defined below) which may be issued pursuant
to Options (as defined below) granted under the Plan from 2,500,000 to
3,250,000. On June 9, 1999, the shareholders of the Corporation approved an
amendment increasing the number of shares of Common Stock which may be issued
pursuant to Options granted under the Plan from 3,250,000 to 3,650,000. On June
26, 2001, the shareholders of the Corporation approved an amendment increasing
the number of shares of Common Stock which may be issued pursuant to Options
granted under the Plan from 3,650,000 to 4,050,000. On June 18, 2002, the
shareholders of the Corporation approved an amendment increasing the number of
shares of Common Stock which may be issued pursuant to Options granted under the
Plan from 4,050,000 to 4,550,000. The Plan was originally executed on October
12, 1993 and incorporates all amendments through June 18, 2002.

SECTION 1.    Definitions

         1.1. "Act" shall mean the Securities Exchange Act of 1934, as amended.

         1.2. "Affiliates" shall mean (a) any corporation, other than the
Corporation, in an unbroken chain of corporations ending with the Corporation if
each of the corporations, other than the Corporation, owns stock possessing
fifty percent (50%) or more of the total combined voting power of all classes of
stock in one of the other corporations in such chain and (b) any corporation,
other than the Corporation, in an unbroken chain of corporations beginning with
the Corporation if each of the corporations, other than the last corporation in
the unbroken chain, owns stock possessing fifty percent (50%) or more of the
total combined voting power of all classes of stock in one of the other
corporations in such chain.

         1.3. "Agreement" shall mean the written agreement between the
Corporation and a Holder evidencing the Option granted by the Corporation and
the understanding of the parties with respect thereto.

         1.4. "Board of Directors" shall mean the board of directors of the
Corporation.

         1.5. "Code" shall mean the Internal Revenue Code of 1986, as amended.

         1.6. "Administrator" shall mean the Administrator appointed pursuant to
Section 3.1 to administer the Plan.

         1.7. "Non-Employee Directors" shall mean directors who meet the
definition of "Non-Employee Directors" under Rule 16b-3 under the Act.

         1.8. "Effective Date" shall mean the date that PMSI Acquisition
Corporation is merged with and into Prime Medical Services, Inc.

         1.9. "Eligible Individuals" shall mean (a) key employees, including
officers and directors who are also employees of the Corporation or of any of
its Affiliates, (b) nonemployee directors and officers of the Corporation or of
any of its Affiliates and (c) consultants and advisors of the Corporation or of
any of its Affiliates who render bona fide services to the Corporation or of any
of its Affiliates; provided such services must not be in connection with the
offer or sale of securities in a capital-raising transaction.

         1.10."Fair Market Value" shall mean:

              (a) If shares of Stock of the same class are listed or admitted to
unlisted trading privileges on any national or regional securities exchange at
the date of determining the Fair Market Value, the last reported sale price on
such exchange on the last business day prior to the date in question; or

              (b) If shares of Stock of the same class shall not be listed or
admitted to unlisted trading privileges as provided in Subparagraph 1.10(a) and
sales prices therefor in the over-the-counter market shall be reported by the
National Association of Securities Dealers, Inc. Automated Quotations, Inc.
("NASDAQ") National Market System at the date of determining the Fair Market
Value, the last reported sale price so reported on the last business day prior
to the date in question; or

              (c) If shares of Stock of the same class shall not be listed or
admitted to unlisted trading privileges as provided in Subparagraph 1.10(a) and
sales prices therefor shall not be reported by the NASDAQ National Market System
as provided in Subparagraph 1.10(b), and bid and asked prices therefor in the
over-the-counter market shall be reported by NASDAQ (or, if not so reported, by
the National Quotation Bureau Incorporated) at the date of determining the Fair
Market Value, the average of the closing bid and asked prices on the last
business day prior to the date in question; and

              (d) If shares of Stock of the same class shall not be listed or
admitted to unlisted trading privileges as provided in Subparagraph 1.10(a) and
sales prices or bid and asked prices therefor shall not be reported by NASDAQ
(or the National Quotation Bureau Incorporated) as provided in Subparagraph
1.10(b) or Subparagraph 1.10(c) at the date of determining the Fair Market
Value, the value determined in good faith by the Administrator.

For purposes of valuing Incentive Options, the Fair Market Value of Stock shall
be determined without regard to any restriction other than one which, by its
terms, will never lapse.

         1.11."Holder" shall mean an Eligible Individual to whom an Option has
been granted.

         1.12."Incentive Options" shall mean stock options that are intended to
satisfy the requirements of section 422A of the Code.

         1.13."Non-Incentive Options" shall mean stock options that do not
satisfy the requirements of section 422A of the Code.

         1.14."Options" shall mean either Incentive Options or Non-Incentive
Options, or both.

         1.15."Stock" shall mean the Corporation's authorized common stock,
$.01 par value, together with any other securities with respect to which Options
granted hereunder may become exercisable.

SECTION 2.    Stock and Maximum Number of Shares Subject to the Plan.

         2.1. Description of Stock and Maximum Shares Allocated. The Stock which
Options granted hereunder give a Holder the right to purchase may be unissued or
reacquired shares of Stock, as the Corporation may, in its sole and absolute
discretion, from time to time determine.

         Subject to the adjustments provided for in Paragraph 6.7 hereof, the
aggregate number of shares of Stock to be issued pursuant to the exercise of all
Options granted hereunder may equal but shall not exceed 4,550,000 shares of
Stock.

         2.2. Restoration of Unpurchased Shares. If an Option granted hereunder
expires or terminates for any reason during the term of this Plan and prior to
the exercise of the Option in full, the shares of Stock subject to but not
issued under such Option shall again be available for Options granted hereunder
subsequent thereto.

SECTION 3.    Administration of the Plan.

         3.1. Administrator. An administrative body designated by the Board of
Directors shall administer the Plan (the "Administrator"). The Board of
Directors may designate itself as the Administrator or appoint two or more
Non-Employee Directors to a committee which shall serve as the Administrator.

         3.2. Meetings and Actions of Administrator. The Administrator shall
hold its meetings at such times and places as it may determine. All decisions
and determinations of the Administrator shall be made by the majority vote or
decision of all of its members present at a meeting; provided, however, that any
decision or determination reduced to writing and signed by all of the members of
the Administrator shall be as fully effective as if it had been made at a
meeting duly called and held. The Administrator may make any rules and
regulations for the conduct of its business that are not inconsistent with the
provisions hereof and with the bylaws of the Corporation as it may deem
advisable.

         3.3. Administrator's Powers. Subject to the express provisions hereof,
the Administrator shall have the authority, in its sole and absolute discretion,
(a) to adopt, amend, and rescind administrative and interpretive rules and
regulations relating to the Plan; (b) to determine the terms and provisions of
the respective Agreements (which need not be identical), including provisions
defining or otherwise relating to (i) subject to Section 6 of the Plan, the term
and the period or periods and extent of exercisability of the Options, (ii) the
extent to which the transferability of shares of Stock issued upon exercise of
Options is restricted, and (iii) the effect of approved leaves of absence
(consistent with any applicable regulations of the Internal Revenue Service);
(c) to accelerate the time of exercisability of any Option that has been
granted; (d) to construe the respective Agreements and the Plan; and (e) to make
all other determinations and perform all other acts necessary or advisable for
administering the Plan, including the delegation of such ministerial acts and
responsibilities as the Administrator deems appropriate. The Administrator may
correct any defect or supply any omission or reconcile any inconsistency in the
Plan or in any Agreement in the manner and to the extent it shall deem expedient
to carry it into effect, and it shall be the sole and final judge of such
expediency. The Administrator shall have full discretion to make all
determinations on the matters referred to in this Paragraph 3.3; such
determinations shall be final, binding and conclusive.

SECTION 4.    Eligibility and Participation.

         4.1. Eligible Individuals. Options may be granted hereunder only to
persons who are Eligible Individuals at the time of the grant thereof.
Notwithstanding any provision contained herein to the contrary, a person shall
not be eligible to receive an Incentive Option hereunder unless he is an
employee of the Corporation or an Affiliate, nor shall a person be eligible to
receive an Incentive Option hereunder if he, at the time such Option is granted,
would own (within the meaning of sections 422A and 425 of the Code) stock
possessing more than ten percent (10%) of the total combined voting power or
value of all classes of stock of the Corporation or of an Affiliate unless at
the time such Incentive Option is granted the exercise price per share of Stock
is at least one hundred and ten percent (110%) of the Fair Market Value of each
share of Stock to which the Incentive Option relates and the Incentive Option is
not exercisable after the expiration of five years from the date it is granted.

         4.2  No Right to Option.  The  adoption of the Plan shall not be deemed
to give any person a right to be granted an Option.

SECTION 5.    Grant of Options and Certain Terms of the Agreements.

         Subject to the express provisions hereof, the Administrator shall
determine which Eligible Individuals shall be granted Options hereunder from
time to time. In making grants, the Administrator shall take into consideration
the contribution the potential Holder has made or may make to the success of the
Corporation or its Affiliates and such other considerations as the Administrator
may from time to time specify. The Administrator shall also determine the number
of shares subject to each of such Options, and shall authorize and cause the
Corporation to grant Options in accordance with such determinations.

         The date on which the Administrator completes all action constituting
an offer of an Option to an individual, including the specification of the
number of shares of Stock to be subject to the Option, shall be the date on
which the Option covered by an Agreement is granted, even though certain terms
of the Agreement may not be at such time determined and even though the
Agreement may not be executed until a later time. In no event, however, shall an
Optionee gain any rights in addition to those specified by the Administrator in
its grant, regardless of the time that may pass between the grant of the Option
and the actual execution of the Agreement by the Corporation and the Optionee.

         Each Option granted hereunder shall be evidenced by an Agreement,
executed by the Corporation and the Eligible Individual to whom the Option is
granted, incorporating such terms as the Administrator shall deem necessary or
desirable. More than one Option may be granted hereunder to the same Eligible
Individual and be outstanding concurrently hereunder. In the event an Eligible
Individual is granted both one or more Incentive Options and one or more
Non-Incentive Options, such grants shall be evidenced by separate Agreements,
one for each of the Incentive Option grants and one for each of the
Non-Incentive Option grants.

         Each Agreement may contain or otherwise provide for conditions giving
rise to the forfeiture of the Stock acquired pursuant to an Option granted
hereunder or otherwise and such restrictions on the transferability of shares of
the Stock acquired pursuant to an Option granted hereunder or otherwise as the
Administrator in its sole and absolute discretion shall deem proper or
advisable. Such conditions giving rise to forfeiture may include, but need not
be limited to, the requirement that the Holder render substantial services to
the Corporation or its Affiliates for a specified period of time. Such
restrictions on transferability may include, but need not be limited to, options
and rights of first refusal in favor of the Corporation and shareholders of the
Corporation other than the Holder of such shares of Stock who is a party to the
particular Agreement or a subsequent holder of the shares of Stock who is bound
by such Agreement. In addition, no Option may be exercisable for a period of
more than ten years from the date the Option is granted.

SECTION 6.    Terms and Conditions of Options.

         All Options granted hereunder shall comply with, be deemed to include,
and shall be subject to the following terms and conditions:

         6.1. Number of Shares. Each Agreement shall state the number of shares
of Stock to which it relates.

         6.2. Exercise Price. Each Agreement shall state the exercise price per
share of Stock. The exercise price per share of Stock subject to an Incentive
Option shall not be less than the greater of (a) the par value per share of the
Stock or (b) 100% of the Fair Market Value per share of the Stock on the date of
the grant of the Option. The exercise price per share of Stock subject to a
Non-Incentive Option shall be determined by the Administrator upon the granting
of the Non-Incentive Option.

         6.3. Automatic Options. Notwithstanding Paragraph 6.2, on the Effective
Date the persons then holding unexercised options granted pursuant to the 1990
Stock Option Plan and Second Amended and Restated Stock Option Plan of Prime
Medical Services, Inc. ("Prime Plans"), shall automatically be granted
Non-Incentive Options under the Plan covering the same number of shares of
Stock, at the same exercise price and for the same term as set forth in the
options granted to such persons under the Prime Plans. The grant of such
Non-Incentive Options shall be in cancellation of such options granted to such
persons under the Prime Plans.

         6.4. Medium and Time of Payment, Method of Exercise, and Withholding
Taxes. The exercise price of an Option shall be payable upon the exercise of the
Option in cash or by certified or cashier's check payable to the order of the
Corporation (or by personal check if agreed to by the Corporation), or, with the
consent of the Administrator, with shares of Stock of the Corporation owned by
the Holder, including a multiple series of exchanges of such Stock, or with the
consent of the Administrator, by a combination of cash and such shares. Exercise
of an Option shall not be effective until the Corporation has received written
notice of exercise. Such notice must specify the number of whole shares to be
purchased and be accompanied by payment in full of the aggregate exercise price
of the number of shares purchased. The Corporation shall not in any case be
required to sell, issue, or deliver a fractional share of Stock with respect to
any Option.

         The Administrator may, in its discretion, require a Holder to pay to
the Corporation at the time of exercise of an Option or portion thereof the
amount that the Corporation deems necessary to satisfy its obligation to
withhold Federal, state or local income or other taxes incurred by reason of the
exercise. Where the exercise of an Option does not give rise to an obligation to
withhold Federal income or other taxes on the date of exercise, the Corporation
may, in its discretion, require a Holder to place shares of Stock purchased
under the Option in escrow for the benefit of the Corporation until such time as
Federal income or other tax withholding is no longer required with respect to
such shares or until such withholding is required on amounts included in the
gross income of the Holder as a result of the exercise of an Option or the
disposition of shares of Stock acquired pursuant thereto. At such later time,
the Corporation, in its discretion, may require a Holder to pay to the
Corporation the amount that the Corporation deems necessary to satisfy its
obligation to withhold Federal, state or local income or other taxes incurred by
reason of the exercise of the Option or the disposition of shares of Stock. Upon
receipt of such payment by the Corporation, such shares of Stock shall be
released from escrow to the Holder.

         6.5. Term, Time of Exercise, and Transferability of Options. In
addition to such other terms and conditions as may be included in a particular
Agreement granting an Option, an Option shall be exercisable during a Holder's
lifetime only by the Holder or by the Holder's guardian or legal representative.
Incentive Options shall not be transferable other than by will or the laws of
descent and distribution. Non-Incentive Options shall not be transferable other
than by will or the laws of descent and distribution, or upon the express prior
written consent of the Administrator in each instance. The provisions of the
remainder of this paragraph shall apply to the extent a Holder's Agreement does
not expressly provide otherwise. If a Holder ceases to be an Eligible
Individual, the Option shall terminate ninety days after such Holder ceases to
be an Eligible Individual. Notwithstanding the foregoing, if a Holder ceases to
be an Eligible Individual by reason of (a) disability (as defined in section
105(d)(4)), or (b) death, then the Holder shall have the right for twelve months
after the date of disability or death to exercise an Option to the extent such
Option is exercisable on the date of his disability.

         That portion of the Option which is not exercisable on the date the
Holder ceases to be an Eligible Individual shall terminate and be forfeited to
the Corporation on the date of such cessation.

         Notwithstanding any other provision of this Plan, no Incentive Option
shall be exercisable after the expiration of ten years from the date it is
granted, or the period specified in Paragraph 4.1, if applicable. The
Administrator shall have authority to prescribe in any Agreement that the Option
evidenced thereby may be exercised in full or in part as to any number of shares
subject thereto at any time or from time to time during the term of the Option,
or in such installments at such times during said term as the Administrator may
prescribe. Except as provided above and unless otherwise provided in any
Agreement, an Option may be exercised at any time or from time to time during
the term of the Option. Such exercise may be as to any or all whole (but no
fractional) shares which have become purchasable under the Option.

         Within a reasonable time or such time as may be permitted by law after
the Corporation receives written notice that the Holder has elected to exercise
all or a portion of an Option, such notice to be accompanied by payment in full
of the aggregate Option exercise price of the number of shares of Stock
purchased, the Corporation shall issue and deliver a certificate representing
the shares acquired in consequence of the exercise and any other amounts payable
in consequence of such exercise. In the event that a Holder exercises both an
Incentive Option, or portion thereof, and a Non-Incentive Stock Option, or a
portion thereof, separate Stock certificates shall be issued, one for the Stock
subject to the Incentive Option and one for the Stock subject to the
Non-Incentive Stock Option. The number of the shares of Stock transferable due
to an exercise of an Option under this Plan shall not be increased due to the
passage of time, except as may be provided in an Agreement. However, this number
of such shares of Stock which are transferable may increase due to the
occurrence of certain events which are fully described in Paragraph 6.7.

         Nothing herein or in any Option granted hereunder shall require the
Corporation to issue any shares upon exercise of any Option if such issuance
would, in the opinion of counsel for the Corporation, constitute a violation of
the Securities Act of 1933, as amended, or any similar or superseding statute or
statutes, or any other applicable statue or regulation, as then in effect. At
the time of any exercise of an Option, the Corporation may, as a condition
precedent to the exercise of such Option, require from the Holder of the Option
(or in the event of his death, his legal representatives, heirs, legatees, or
distributees) such written representations, if any, concerning his intentions
with regard to the retention or disposition of the shares being acquired by
exercise of such Option and such written covenants and agreements, if any, as to
the manner of disposal of such shares as, in the opinion of counsel to the
Corporation, may be necessary to ensure that any disposition by such Holder (or
in the event of his death, his legal representatives, heirs, legatees, or
distributees), will not involve a violation of the Securities Act of 1933, as
amended, or any similar or superseding statute or statutes, or any other
applicable state or federal statute or regulation, as then in effect.
Certificates for shares of Stock, when issued, may have the following or similar
legend, or statements of other applicable restrictions, endorsed thereon, and
may not be immediately transferable:

         The shares of Stock evidenced by this certificate have been issued to
         the registered owner in reliance upon written representations that
         these shares have been purchased for investment. These shares have not
         been registered under the Securities Act of 1933, as amended, or any
         applicable state securities laws, in reliance upon an exception from
         registration. Without such registration, these shares may not be sold,
         transferred, assigned or otherwise disposed of unless, in the opinion
         of the Corporation and its legal counsel, such sale, transfer,
         assignment or disposition will not be in violation of the Securities
         Act of 1933, as amended, applicable rules and regulations of the
         Securities and Exchange Commission, and any applicable state securities
         laws.

         6.6. Limitation on Aggregate Value of Shares That May Become First
Exercisable During Any Calendar Year Under an Incentive Option. Except as is
otherwise provided in the second paragraph of Paragraph 6.7 hereof, with respect
to any Incentive Option granted under this Plan, the sum of:

         (a)  the aggregate Fair Market Value of shares of Stock subject to such
              Incentive Option that first become purchasable in a calendar year
              under such Incentive Option, and

         (b)  the aggregate Fair Market Value of shares of Stock or stock of any
              Affiliate (or a predecessor of the Corporation or an Affiliate)
              subject to any other incentive stock option (within the meaning of
              section 422A of the Code) of the Corporation or its Affiliates (or
              a predecessor corporation of any such corporation), that first
              become purchasable in a calendar year under such incentive stock
              option may not (with respect to any Holder) exceed $100,000, with
              such Fair Market Value to be determined as of the date the
              Incentive Option or such other incentive stock option is granted.

For purposes of this Paragraph 6.6, "predecessor corporation" means (i) a
corporation that was a party to a transaction described in section 425(a) of the
Code (or which would be so described if a substitution or assumption under such
section had been effected) with the Corporation, (ii) a corporation which, at
the time the new incentive stock option (within the meaning of section 422A of
the Code) is granted, is an Affiliate of the Corporation or a predecessor
corporation of any such corporations, or (iii) a predecessor corporation of any
such corporations.

         6.7. Adjustments Upon Changes in Capitalization. Notwithstanding any
other provision hereof, in the event of any change in the number of outstanding
shares of Stock effected without receipt of consideration therefor by the
Corporation, by reason of a stock dividend, or split, combination, exchange of
shares or other recapitalization, merger, or otherwise, in which the Corporation
is the surviving corporation (1) the aggregate number and class of the reserved
shares, (2) the number and class of shares subject to each outstanding Option
and (3) the exercise price of each outstanding Option shall be automatically
adjusted to equitably reflect the effect thereon of such change (provided,
however, that any fractional share resulting from such adjustment may be
eliminated). In the event of a dispute concerning such adjustment, the
Administrator has full discretion to determine the resolution of the dispute.
Such determination shall be final, binding and conclusive. The number of
reserved shares or the number of shares subject to any outstanding Option shall
be automatically reduced by any fraction included therein which results from any
adjustment made pursuant to this Paragraph 6.7.

         The following provisions of this Paragraph 6.7 shall apply unless a
Holder's Agreement provides otherwise. In the event of:

         (a)  a dissolution or liquidation of the Corporation,

         (b)  a merger or consolidation (other than a merger effecting a
re-incorporation of the Corporation in another state or any other merger or a
consolidation in which the shareholders of the surviving corporation and their
proportionate interests therein immediately after the merger or consolidation
are substantially identical to the shareholders of the Corporation and their
proportionate interests therein immediately prior to the merger or
consolidation) in which the Corporation is not the surviving corporation (or
survives only as a subsidiary of another corporation in a transaction in which
the shareholders of the parent of the Corporation and their proportionate
interests therein immediately after the transaction are not substantially
identical to the shareholders of the Corporation and their proportionate
interests therein immediately prior to the transaction; provided, however, that
the Administrator may at any time prior to such a merger or consolidation
provide by resolution that the foregoing provisions of this parenthetical shall
not apply if a majority of the board of directors of such parent immediately
after the transaction consists of individuals who constituted a majority of the
Board of Directors immediately prior to the transaction), or

         (c)  a transaction in which any person (other than a shareholder of the
Corporation  that already is the owner of 50% or more of the total combined
voting power of all classes of the  Corporation on the date of the Holder's
Agreement) becomes the owner of 50% or more of the total combined voting power
of all classes of stock of the Corporation (provided, however, that the
Administrator may at any time prior to such transaction provide by resolution
that this subparagraph (c) shall not apply if such acquiring person is a
corporation and a majority of the board of directors of the acquiring
corporation immediately after the transaction consists of individuals who
constituted a majority of the Board of Directors immediately prior to the
acquisition of such 50% or more total combined voting power) the Administrator
may, at its election, as of the effective time of such transaction, either
(1) change the number and kind of shares of stock (including substitution of
shares of another corporation) and exercise price in the manner it deems
appropriate, provided, however, that in no event may any change be made under
this Paragraph 6.7 which would constitute a "modification" within the meaning of
section 425(h)(3) of the Code; or (2) purchase the Options from each Holder by
tendering cash equal to the Fair Market Value of the Stock represented by the
Options less the exercise price of the Options specified in each Agreement,
without regard to the determination as to the periods and installments of
exercisability made pursuant to a Holder's Agreement if (and only if) such
Options have not at that time expired or been terminated.

         6.8. Rights as a Shareholder. A Holder shall have no right as a
shareholder with respect to any shares covered by his Option until a certificate
representing such shares is issued to him. No adjustment shall be made for
dividends (ordinary or extraordinary, whether in cash or other property) or
distributions or other rights for which the record date is prior to the date
such certificate is issued, except as provided in Paragraph 6.7 hereof.

         6.9. Modification, Extension and Renewal of Options. Subject to the
terms and conditions of and within the limitations of the Plan, the
Administrator may modify, extend or renew outstanding Options granted under the
Plan, or accept the surrender of Options outstanding hereunder (to the extent
not theretofore exercised) and authorize the granting of new Options hereunder
in substitution therefor (to the extent not theretofore exercised). The
Administrator may not, however, without the consent of the Holder, modify any
outstanding Options so as to specify a higher or lower exercise price or base
amount or accept the surrender of outstanding Incentive Options and authorize
the granting of new Options in substitution therefor specifying a higher or
lower exercise price. In addition, no modification of an Option granted
hereunder shall, without the consent of the Holder, alter or impair any rights
or obligations under any Option theretofore granted hereunder to such Holder
under the Plan, except as may be necessary, with respect to Incentive Options,
to satisfy the requirements of section 422A of the Code.

         6.10.Furnish Information. Each Holder shall furnish to the Corporation
all information requested by the Corporation to enable it to comply with any
reporting or other requirement imposed upon the Corporation by or under any
applicable statute or regulation.

         6.11.Obligation to Exercise; Termination of Employment. The granting of
an Option hereunder shall impose no obligation upon the Holder to exercise the
same or any part thereof. In the event of a Holder's termination of employment
with the Corporation or an Affiliate, the unexercised portion of an Option
granted hereunder shall terminate in accordance with Paragraph 6.5 hereof.

         6.12.Agreement Provisions. The Agreements authorized under the Plan
shall contain such provisions in addition to those required by the Plan
(including, without limitation, restrictions or the removal of restrictions upon
the exercise of the Option and the retention or transfer of shares thereby
acquired) as the Administrator shall deem advisable. Each Agreement shall
identify the Option evidenced thereby as an Incentive Option or a Non-Incentive
Option, as the case may be, and no Agreement shall cover both an Incentive
Option and a Non-Incentive Option. Each Agreement relating to an Incentive
Option granted hereunder shall contain such limitations and restrictions upon
the exercise of the Incentive Option to which it relates as shall be necessary
for the Incentive Option to which such Agreement relates to constitute an
incentive stock option, as defined in section 422A of the Code.

SECTION 7.    Remedies.

         7.1. Attorneys Fees. The Corporation shall be entitled to recover from
a Holder reasonable attorneys' fees incurred in connection with the enforcement
of the terms and provisions of the Plan and any Agreement whether by an action
to enforce specific performance or for damages for its breach or otherwise.

         7.2. Specific Performance. The Corporation shall be entitled to enforce
the terms and provisions of this Paragraph 7, including the remedy of specific
performance, in Travis County, Texas.

SECTION 8.    Duration of Plan.

         No Options will be granted herein after the date that is ten years from
the earlier of (a) the date the Plan is accepted by the Board of Directors or
(b) the date the Plan is approved by the shareholders of the Corporation.

SECTION 9.    Amendment of Plan.

         The Board of Directors may at any time terminate or from time to time
amend or suspend the Plan; provided, however, that no such amendment shall,
without approval of the shareholders of the Corporation, except as provided in
Section 7 hereof, (a) increase the aggregate number of shares of Stock as to
which Options may be granted under the Plan; (b) change the minimum Option
exercise price; (c) increase the maximum period during which Options may be
exercised; or (d) extend the effective period of the Plan. No Option may be
granted during any suspension of the Plan or after the Plan has been terminated
and no amendment, suspension or termination shall, without a Holder's consent,
adversely alter or impair any of the rights or obligations under any Option
theretofore granted to such Holder under the Plan.

SECTION 10.   General.

         10.1.Application of Funds. The proceeds received by the Corporation
from the sale of shares pursuant to Options shall be used for general corporate
purposes.

         10.2.Right of the Corporation and Affiliates to Terminate Employment.
Nothing contained in the Plan, or in any Agreement, shall confer upon any Holder
the right to continue in the employ of the Corporation or any Affiliate, or
interfere in any way with the rights of the Corporation or any Affiliate to
terminate his employment any time.

         10.3.No Liability for Good Faith Determinations. Neither the members of
the Board of Directors nor any member of the Administrator shall be liable for
any act, omission, or determination taken or made in good faith with respect to
the Plan or any Option granted under it, and members of the Board of Directors
and the Administrator shall be entitled to indemnification and reimbursement by
the Corporation in respect of any claim, loss, damage, or expense (including
attorneys' fees, the costs of settling any suit, provided such settlement is
approved by independent legal counsel selected by the Corporation, and amounts
paid in satisfaction of a judgment, except a judgment based on a finding of bad
faith) arising therefrom to the full extent permitted by law and under any
directors and officers liability or similar insurance coverage that may from
time to time be in effect.

         10.4.Information Confidential. As partial consideration for the
granting of each Option hereunder, the Agreement may, in the Administrator's
sole and absolute discretion, provide that the Holder shall agree with the
Corporation that he will keep confidential all information and knowledge that he
has relating to the manner and amount of his participation in the Plan;
provided, however, that such information may be disclosed as required by law and
may be given in confidence to the Holder's spouse, tax and financial advisors,
or to a financial institution to the extent that such information is necessary
to secure a loan. In the event any breach of this promise comes to the attention
of the Administrator, it shall take into consideration such breach, in
determining whether to recommend the grant of any future Option to such Holder,
as a factor militating against the advisability of granting any such future
Option to such individual.

         10.5.Other Benefits. Participation in the Plan shall not preclude the
Holder from eligibility in any other stock option plan of the Corporation or any
Affiliate or any old age benefit, insurance, pension, profit sharing,
retirement, bonus, or other extra compensation plans which the Corporation or
any Affiliate has adopted, or may, at any time, adopt for the benefit of its
employees.

         10.6.Execution of Receipts and Releases. Any payment of cash or any
issuance or transfer of shares of Stock to the Holder, or to his legal
representative, heir, legatee, or distributee, in accordance with the provisions
hereof, shall, to the extent thereof, be in full satisfaction of all claims of
such persons hereunder. The Administrator may require any Holder, legal
representative, heir, legatee, or distributee, as a condition precedent to such
payment, to execute a release and receipt therefor in such form as it shall
determine.

         10.7.No Guarantee of Interests. Neither the Administrator nor the
Corporation gurarantees the Stock of the Corporation from loss or depreciation.

         10.8.Payment of Expenses. All expenses incident to the administration,
termination, or protection of the Plan, including, but not limited to, legal and
accounting fees, shall be paid by the Corporation or its Affiliates; provided,
however, the Corporation or an Affiliate may recover any and all damages, fees,
expenses, and/or costs arising out of any actions taken by the Corporation to
enforce its rights hereunder.

         10.9.Corporation Records. Records of the Corporation or its Affiliates
regarding the Holder's period of employment, termination of employment and the
reason therefor, leaves of absence, re-employment, and other matters shall be
conclusive for all purposes hereunder, unless determined by the Administrator to
be incorrect.

         10.10.Information. The Corporation and its Affiliates shall, upon
request or as may be specifically required hereunder, furnish or cause to be
furnished, all of the information or documentation which is necessary or
required by the Administrator to perform its duties and functions under the
Plan.

         10.11.No Liability of Corporation. The Corporation assumes no
obligation or responsibility to the Holder or his legal representatives, heirs,
legatees, or distributees for any act of, or failure to act on the part of, the
Administrator.

         10.12.Corporation Action. Any action required of the Corporation shall
be by resolution of its Board of Directors or by a person authorized to act by
resolution of the Board of Directors.

         10.13.Severability. If any provision of this Plan is held to be illegal
or invalid for any reason, the illegality or invalidity shall not affect the
remaining provisions hereof, but such provision shall be fully severable and the
Plan shall be construed and enforced as if the illegal or invalid provision had
never been included herein.

         10.14.Notices. Whenever any notice is required or permitted hereunder,
such notice must be in writing and personally delivered or sent by mail or by a
nationally recognized courier service. Any notice required or permitted to be
delivered hereunder shall be deemed to be delivered on the date on which it is
personally delivered, or, if mailed, whether actually received or not, on the
third business day after it is deposited in the United States mail, certified or
registered, postage prepaid, addressed to the person who is to receive it at the
address which such person has previously specified by written notice delivered
in accordance herewith or, if by courier, twenty-four hours after it is sent,
addressed as described in this Section. The Corporation or a Holder may change,
at any time and from time to time, by written notice to the other, the address
which it or he had previously specified for receiving notices. Until changed in
accordance herewith, the Corporation and each Holder shall specify as its and
his address for receiving notices the address set forth in the Agreement
pertaining to the shares to which such notice relates.

         10.15.Waiver of Notice. Any person entitled to notice hereunder may
waive such notice.

         10.16.Successors. The Plan shall be binding upon the Holder, his legal
representatives, heirs, legatees and distributees upon the Corporation, its
successors, and assigns, and upon the Administrator, and its successors.

         10.17.Headings. The titles and headings of Sections and Paragraphs are
included for convenience of reference only and are not to be considered in
construction of the provisions hereof.

         10.18.Governing Law. All questions arising with respect to the
provisions of the Plan shall be determined by application of the laws of the
State of Texas except to the extent Texas law is preempted by federal law.
Questions arising with respect to the provisions of an Agreement that are
matters of contract law shall be governed by the laws of the state specified in
the Agreement, except to the extent preempted by federal law and except to the
extent that Texas corporate law conflicts with the contract law of such state,
in which event Texas corporate law shall govern. The obligation of the
Corporation to sell and deliver Stock hereunder is subject to applicable laws
and to the approval of any governmental authority required in connection with
the authorization, issuance, sale, or delivery of such Stock.

         10.19.Word Usage. Words used in the masculine shall apply to the
feminine where applicable, and wherever the context of this Plan dictates, the
plural shall be read as the singular and the singular as the plural.

         IN WITNESS WHEREOF, Prime Medical Services, Inc., acting by and through
its officer hereunto duly authorized, has executed this Plan on this the 18th
day of June, 2002.

                          PRIME MEDICAL SERVICES, INC.


                          By: /s/ John Q. Barnidge
                              -----------------------------------------
                              John Q. Barnidge, Senior Vice President
                              and Chief Financial Officer